TriggerShims.com Bolt Shim Page

Index for Bolt Shim on Our Website

Index for Bolt Shim Sizes

Bolt Shim Reviews - Under Construction

TECH TIP: Lance's Bolt Shim Instructions ~ A General Guide

TECH TIP: Lance's Headspace and Rim Thickness Guide

LANCE'S TECH TIP: Rimfire Headspace

Tech Tip: Anschutz 1712 w/ Targets

Lance,
I just wanted to say, that your bolt shims are just what the doctor ordered.
It is not often that you find such a simple fix to anything, but these truly are.
Thank You! Trent in UT

Index for Bolt Shims on Our Website

Rimfire Rifle Bolt Shim Index

BoltShim-INDEX 9/24

Our Ever Expanding Selection of Rimfire Rifle Bolt Shims

Links to Our List of .22 Rifle Bolt and Barrel Shims

Anschutz 54 ~ Now In Stock!
Bergara B-14R Rimfire Bolt Shims
CZ and BRNO Rimfire Bolt Shims
CZ 457 Rimfire Bolt Shims
Kimber 82G Target Rifle Bolt Shims
Lithgow LA 101 and SA 2020 Rimfire
Marlin 80 / 983 Rimfire Bolt Shims
Mossberg 44 U.S. Bolt
Mossberg 144 LSB Bolt
Remington 5 Bolt Shims
Remington 40X Bolt Shims
Remington 504T Bolt Shims
Remington 513T / 521T Rimfire Rifle
Remington 540X Bolt Shims
Ruger American Rimfire Bolt Shims
Ruger 77/17 77/22 Bolt Shims
Savage BMag Bolt Shims
Savage MKII Bolt Shims - Prototype
Springfield Armory Model 2020 Rimfire
Suhl 150 Rimfire Rifle
Tikka T1x and Sako P72 / M78 Rimfire Rifle / Walther KK300
Turbo V3 / Flash Turbo Bolt Shims
Walther KK500 Rimfire Bolt Shims
Winchester 43 and 52 Bolt Shims
Winchester 69 and 75 Bolt Shims

~ Barrel Shims ~

NOTE: email me to be put on a list to Request a New Bolt Shim ~ Send Lance an Email ~

Unsolicited Testimonial:
Just a friendly note on the bolt shims I purchased and installed. My 5 shot group went from dime size at 50 yds to everyone touching and not being able to count individual holes.
Thank You for a Great Product ~ Riley in WV

Unsolicited Testimonial:
Lance, I simply wanted to say thank you for providing Bolt Shims. My first one installed was on my Bergara B-14 22 Trainer. I won the club season matches in 2022. It's more accurate now than my winning season. After seeing an improvement, in an already accurate rifle, I've shimmed my Bergara Shooting Rimfire barreled action, two CZ 457, my 2020 Springfield, and my my 54 Annie. The Anschutz allowed for 5th place in the IR 50/50 factory class last year. I shimmed it yesterday. The common fliers were less frequent and overall consistency was improved. A noticeable improvement was seen in all the rifles.
Thanks again for offering a great product ~ Rob in NC

Index for Bolt Shim Sizes

V2.2-BOX~BS-SIZES 8/25

Selection of Rimfire Rifle Bolt Shims Sorted by Size

BOLT SHIMS
Sorted by I.D. Size

.357 x .595 Remington 540X Bolt

.376 x .500 Ruger American Rimfire Rifle Bolt Shims

.376 x .565 CZ 457 Rimfire Bolt

.376 x .690 Orphan Bolt Shim

.442 x .555 Remington 5 / Zastava

.442 x .595 Mossberg 44 U.S. Bolt and H&R M12

.442 x .648 Ruger 77/22 Bolt

.450 x .565 Winchester 69A / 75S Bolt

.450 x .595 Marlin 983 Bolt & Remington 504T & Glenfield

.480 x .570 Remington 513

.480 x .610 Mossberg 144 LSB

.480 x .640 Savage B.Mag Bolt

.480 x .751 Walther KK500 Bolt Shim

.500 x .610 Kimber 82 U.S. Bolt

.500 x .648 Bergara B14-R Bolt

.511 x .648 Turbo V3 / Flash Turbo

.511 x .648 Winchester 52 / Suhl 150 Bolt / Flash Turbo

.532 x .640 Anschutz 54

.555 x .670 Tikka T1x - Sako / Weihrauch / Walther KK300

.565 x .670 Holeshot 2500X

.565 x .690 New for 2025

.570 x .690 Remington 40X Bolt

.595 x .690 Lithgow LA101 Bolt / Springfield 2020 Rimfire

.610 x .690 CZ / BRNO Bolt ~ Also Fits: Diana R22, Webley & Scott Xocet

.622 x .751 Walther KKM - KKJ

BARREL SHIMS
Sorted by I.D. Size

.690 X .900 10/22 Rifle Barrel Shims

.710 X .850 CZ Barrel Shim

.710 X .900 CZ XL Barrel Shim

.710 X .950 CZ XXL Barrel Shim

.730 X .900 2500X Barrel Shim

.751 X .900 Bull Barrel Shims

BOLT SHIMS
Sorted by O.D. Size

.376 x .500 Ruger American Rimfire Rifle Bolt Shims

.442 x .555 Remington 5 / Zastava

.376 x .565 CZ 457 Rimfire Bolt

.450 x .565 Winchester 69A / 75S Bolt

.480 x .570 Remington 513

.357 x .595 Remington 540X Bolt

.442 x .595 Mossberg 44 U.S. Bolt and H&R M12

.450 x .595 Marlin 983 Bolt & Remington 504T & Glenfield

.500 x .610 Kimber 82 U.S. Bolt

.480 x .610 Mossberg 144 LSB

.532 x .640 Anschutz 54

.442 x .648 Ruger 77/22 Bolt

.480 x .640 Savage B.Mag Bolt

.500 x .648 Bergara B14-R Bolt

.511 x .648 Turbo V3 / Flash Turbo

.511 x .648 Winchester 52 / Suhl 150 Bolt / Flash Turbo

.555 x .670 Tikka T1x - Sako / Weihrauch / Walther KK300

.565 x .670 Holeshot 2500X

.376 x .690 Orphan Bolt Shim

.565 x .690 New for 2025

.570 x .690 Remington 40X Bolt

.595 x .690 Lithgow LA101 Bolt / Springfield 2020 Rimfire

.610 x .690 CZ / BRNO Bolt ~ Also Fits: Diana R22, Webley & Scott Xocet

.480 x .751 Walther KK500 Bolt Shim

.622 x .751 Walther KKM / KKJ

BARREL SHIMS
Sorted by O.D. Size

.710 X .850 CZ Barrel Shim

.690 X .900 10/22 Rifle Barrel Shims

.710 X .900 CZ XL Barrel Shim

.730 X .900 2500X Barrel Shim

.751 X .900 Bull Barrel Shims

.710 X .950 CZ XXL Barrel Shim

Review

Hi Lance, Just wanted to let you know that I received the bolt shims, installed them, and am very happy with the accuracy improvement. I changed the barrel on my 457 from 22 lr to 22 mag, and it shot well with several brands of ammo. However, I need to hunt with lead-free ammo around here, and the only kind I can get is Winchester Varmint LF. I was shooting groups around 2 MOA, and had quite a few misfires. My groups tightened to about half that with the shims, and I also cut way down on misfires. Thanks! James in CA

Bolt Shim Instructions

LANCE'S TECH TIP:
Rimfire Bolt Shim Installation
~ A General Guide ~

Unlike centerfire cartridges where headspace is on the shoulder, .22 LR is rim headspaced—the dimension from the bolt face to the barrel breech face (rim seat) determines how much "play" or clearance the cartridge rim has.

Rimmed Cartridges use the thickness of the cartridge rim for head-spacing.
.22 Rimfire Cartridges Headspace on the Case Rim.
The Actual Headspace is in the Recessed Face of the Bolt.
You Must Make Sure this Recessed Bolt Face is Equal To or Deeper Than Your Rim for Safety
Generally speaking, there is extra room left in production guns between the Bolt and Breech to accommodate a wide variety of ammunition with varying rim thicknesses.
You should first measure the depth of your bolt face pocket to ensure it meets SAAMI Headspace minimum depth.
Shimming between the two bolt halves ensures the bolt is seating the cartridge up gently against the breech with your chosen brand of ammunition.
You can use our color-coded numbered shims like a gauge to find when the bolt face touches the barrel breech face, and then calculate where you want to be with your bolt headspace depth and rim thickness measurements.
I cannot tell you which shim best works with your rifle; you decide that yourself by fitting and feel and by shooting.
Installing Bolt Shims requires fitting by hand and checking with the Bolt installed in the Rifle and Locked Down - you do not measure with the Bolt out of the Rifle.
To establish the Bolt/Breech fit, shims are installed and fitted on an empty chamber.
If possible, it may give you a better feel if you leave the extractors off some rifles while fitting shims.
Start with a 4 or 5 pack of shims, install the .0015" or .002" thinnest shim and see how your bolt closes. If it seems to close as normal, then continue to install each thicker shim until the bolt starts to close harder than normal, stacking shims if necessary.
At the point where your bolt begins to close hard, that was the amount of slack that was in your bolt, measured by whatever shim or shims combined were needed to bring the bolt up tight to the breech.
Now it is best to remove that shim and step back one number. For example, if a .005" Red Shim causes the bolt handle to close harder than normal, then take it out and install a .004" Purple Shim.
If you have to force or put undue stress on your bolt to close it, you should reduce the number of shims.
You will generally only use 1 of the 4 or 5 shims in the package, but you can stack shims together if needed.
When you have the correct shim installed, your bolt should close normally or just (ever-so) slightly tighter than normal.
If the bolt closes slightly tight, it is best to back up one step, remove .001".
Put a very small drop of oil on the shim.
Now you can go to the range and, with the barrel pointed in a safe direction, once again check fit with your favorite ammo.
Due to variations in rim thickness, you may have to reduce the thickness of shims. Remember, you have already removed all the excess headspace from the bolt/breech, so now the only thing to do is remove thickness (shims) if/as needed to get to your sweet spot or required headspace for the rim thickness of your favorite cartridge.
For longest shim life, use a drop of oil or a (very small amount of) grease on your shim.
If you have to force or put undue stress on your bolt to close it, you should reduce the number of shims.
A minimum of clearance should be maintained while maintaining proper headspace. Do not put undue stress on the bolt by shimming too tightly as it is unnecessary!
At no time do you want to force the bolt to close or to crush the rim. Did I explain that clearly?
Forcing the Bolt to Close will put premature wear on the bolt shims and will not increase accuracy.
If you have any questions, use a headspace gauge to check for proper headspace.
Bolt Shims have in many instances cured light strikes.
Will they help with accuracy? Don't take my word for it. Read our Customer Reviews or ask our Customers.
Simply Chambering More Consistently Yields More Consistent Results.
Your Satisfaction is Guaranteed. If you feel you receive no benefit, you may send your shims back to TriggerShims for a Full Refund.

Click Here to Open Instructions in a Printable PDF:
LANCE'S TECH TIP: Rimfire Bolt Shim Installation Instructions

TriggerShims.com Shim Thickness Color Code

All TriggerShims Gun Shims are Made in the USA from Precision Brand American Made 304 Stainless Steel Stock and have a Guaranteed Factory Tolerance of plus or minus 10%.
Shims are marked with colored permanent marker that will wear off or strip off with oils or solvents.
If you are testing, plan on keeping your shims in separate marked small envelopes or using a micrometer.

.0015" - Yellow
.002" - Black
.003" - Blue
.004" - Purple
.005" - Red
.006" - Orange
.007" - Green
.008" - Pink
.009" - Brown
.010" - Yellow

TriggerShims Bolt Shim Instructions Copyright 2008 - 2025 V7/2025

Tech Tip: Rimfire Headspace

Lance's Tech Tip: Match Chamber and Rimfire Headspace

The Match Chamber, and Rimfire Headspace are two different things.
Generally a Match Chamber is simply a chamber that is held to a tighter tolerance than a production rifle chamber using Premium or Match Chamber Reamers
A discussion of the Match Rimfire Chamber by Eagle Eye Shooting can be found here: (link) https://youtu.be/PzFCbOn_evE

The Chamber is in the barrel, and with a rimfire rifle, the headspace is in the bolt face. The bolt face is manufactured or machined to an average to function with many types of ammunition, both thick rims and thin, and the bolt is installed in a production rifle with additional space so as not to require hand fitting. Knowing how this works you can check and sometimes the bolt can be adjusted to better fit your favorite ammunition.

By reading and understanding the information and examples on the CZ page titled;
TECH TIP PDF: Measuring Headspace on your CZ 457 Rifle by Jack Behrman (link) https://www.triggershims.com/manuals/measuring_headspace_CZ_457.pdf
you can see that:
1) The Chamber is in the Barrel, and does not affect the Headspace
2) The Headspace is in the Bolt, and it's depth can be measured
3) The distance between closed Bolt Face, and the Barrel Breech can vary several thousandths of an inch.
4) The Bolt can be adjusted to move the face forward using shims, and the Barrel can be set back using a lathe, or forward using shims.

Conditions reported to us over the years by customers on different brands of rimfire rifles but specifically CZ Rimfire Rifles range from too tight and forcing the bolt face against the breech with excessive force, to too loose by as much as 0.006" or more. It is very simple to measure your Bolt Face Headspace using a Depth Micrometer, or Caliper, and then use our shims as a measuring tool to shim the bolt to touch the breech by feel.
See my LANCE'S TECH TIP: Rimfire Bolt Shim Installation ~ A General Guide ~ for more information
Using those two numbers, you can better decide what to adjust for best consistency with the rim thickness of your preferred ammunition. If in the unlikely chance your bolt is too tight from the factory, we manufacture Barrel Shims that can be used to address that problem on CZ rifles by moving the barrel forward. A much more likely scenario is to move a slightly slack bolt forward using our Bolt Shims.
It is a fact that if you more uniformly chamber your rounds, you can expect better accuracy simply through consistency.

Accuracy through Consistency - simply put production rifles have a large headspace to accommodate a wide range of rim thicknesses. Precision shooting involves eliminating variables for best accuracy, and using a bolt shim to adjust the headspace to fit a specific rim thickness better is all this involves.
The same principal used if you were to purchase a long shank replacement barrel, you would need a barrel shim to adjust for optimum headspace.

V10/2024

Headspace Tech Tip

Headspace Tech Tip V1.1

TECH TIP: CZ Rimfire Headspace Tuning for Maximum Accuracy (Bolt & Barrel Shims – All Models)

Rimfire headspace (bolt face to breech face) on CZ rifles (452, 453, 455, 457 and variants) is rim-based. Factory setups often run loose (~0.045" or more), allowing rim "slop" (up to 0.015" per SAAMI) that causes inconsistent primer strikes, cartridge positioning, and bullet entry into the rifling — resulting in flyers and larger groups.

Why tighten it? Reducing play ensures the cartridge chambers the same way every time for uniform ignition and accuracy. As Kurt the Gunsmith shows in his excellent video (click the image below to watch on YouTube), shimming from ~0.045" to ~0.043" "shrunk my groups considerably" on his CZ 457.

These principles apply to all CZ rimfire models — 452, 453, 455, 457 — with the same measurement steps, optimal targets, and safety notes. Bolt shims differ by model (CZ 457 uses .376" x .565" size; older 452/453/455 use .610" x .690"), but barrel shims are the same across all for tight-headspace fixes or barrel swaps.

SAAMI allows 0.043"–0.051" chamber headspace, but precision shooters (benchrest, NRL22, etc.) prefer tighter for consistency.

Kurt the Gunsmith CZ-457 Headspace Video Demo

Optimal Headspace Recommendation (All CZ Models)

Aim for 0.042"–0.043" total clearance.

For Eley (~0.038" rims): 0.041"–0.042" (~0.002"–0.004" clearance; some go to 0.0405" for consistent lots).
For Lapua/SK (~0.041"–0.042" rims): 0.042"–0.043" (~0.001"–0.003" clearance).
Sweet spot for most owners: ~0.042"–0.043" — forgiving across lots, reliable ignition, and proven to tighten groups.

Too loose (> 0.046") → rim float, erratic strikes, flyers
Too tight (< 0.041") → hard closure or failures on thicker rims

Best fix for loose headspace: TriggerShims.com bolt shims — precision 304 stainless steel, color-coded, proudly made in the USA. Install between bolt halves to advance the bolt face forward (e.g., 0.002"–0.003" common). Kurt calls this "the most economical" way — no lathe, no permanent changes. For too-tight cases or barrel swaps, use barrel shims (same for all CZ models).

Step-by-Step: Measuring & Adjusting Headspace on CZ Rifles

Gather Tools
- Depth micrometer (preferred, as Kurt uses) or dial calipers
- Incremental .22 LR headspace gauges — highly recommended:
  John Whidden (national champion, custom rimfire expert, and fellow TriggerShims Brand reseller) makes these stainless sets in 0.001" steps with storage box — perfect for fine-tuning before shimming.
  Link to Whidden Gun Works 👉
- Small punch/screwdriver for bolt disassembly
- TriggerShims.com CZ bolt shim kit (choose 457 or 452/453/455 version; start with 0.0015"–0.003")
- Dummy rounds from your ammo lot
Measure Current Headspace
- Remove barrel (loosen set screws on receiver shoulder for 457/455; similar for older models).
- Measure receiver face to bolt face (rim contact) with depth mic/calipers.
- Measure barrel shoulder protrusion; subtract for headspace (e.g., Kurt's factory ~0.045").
- Confirm with Whidden gauges: Bolt closes smoothly on target (e.g., 0.043"), resists tighter.
- Measure ammo rims (5–10 samples) for average.
Determine Shim Needed
- If 0.045" → want 0.043": Use 0.002" shim (or stack).
- Test closure on gauges/dummies.
Install Bolt Shim
- Disassemble bolt (push handle over, punch pin, remove collar).
- Place shim over firing pin area (front of handle, behind body).
- Reassemble (correct firing pin cam position).
- Reinstall barrel, tighten set screws.
Verify & Fine-Tune
- Re-measure post-shim (use Whidden set).
- Function test dummies: Smooth closure, extractor snaps over rim.
- Live fire: Reliable ignition/extraction, no light strikes.
- Shoot groups at 50 yards — tweak in 0.001" steps.

Safety Notes: Never crush rims (slam-fire risk). Avoid excessive float (misfires/light strikes). Use quality match ammo; sort rims for brand changes. Consult a gunsmith if unsure.

Dial in your CZ rifle today — American-made precision starts here!

Visit TriggerShims.com for CZ bolt shims (our #1 seller — choose 457 or 452/453/455 version) and barrel shims (same for all models). Free economy shipping on shim orders via First Class Mail (tracking upgrade $6 available), proudly the world's largest manufacturer, 100% American-made in Michigan by Lance & Tammy Shively.

For gauges: Check Whidden Gunworks — John Whidden (rimfire legend and TriggerShims customer/reseller) offers top-tier .22 LR sets.

Popular Rim Thicknesses Quick Reference

Eley Tenex/Match: ~0.038"
Lapua Center-X/SLR: ~0.041"–0.042"
SK Rifle Match: ~0.041"–0.042"
CCI Standard Velocity: ~0.043"

Check out these YouTube Video's on Measuring Headspace (links)

ELEY Ammunition – Headspace in .22LR Explained (Watch Video)

The Truth About 22lr Rifle Headspace — Why It’s Not One-Size-Fits-All (Watch Video)

22LR, Does Headspace Matter? (Watch Video)

Questions? Call/text Lance at 517-499-5366 or email Lance@TriggerShims.com. We sincerely appreciate your patronage and love supporting fellow American shooters — God Bless the U.S.A.!

All Material Copyright of Lance Shively 2008 ~ 2026 and Beyond
Developed with research assistance from xAI and Grok

V1.1 - 02/25/2026

Bolt Face Tech Tip

TECH TIP: Bolt Face Rim Recess Depth and Its Effect on Shimmed Headspacing

In .22 LR rimfire rifles, headspace is rim-based — the clearance from the bottom of the bolt face rim recess (also called rim pocket, rim counterbore, or bolt face recess) to the barrel breech face. This recess is the machined depression in the bolt face where the cartridge rim seats when the bolt closes.

The recess depth sets the absolute minimum achievable headspace in a factory or non-machined setup. Bolt shims (like those from TriggerShims.com) advance the bolt forward to reduce excess headspace (slop/float) from factory tolerances, but they cannot reduce headspace below the recess depth without machining the bolt (e.g., facing off the outer raised ring to shallow the recess). Shimming optimizes reliability and accuracy by minimizing rim movement, inconsistent primer strikes, cartridge wobble, and flyers — especially useful for match ammo with thin rims (Eley ~0.038") or thicker ones (CCI Standard Velocity ~0.043").

Why Recess Depth Matters

Deeper recess (e.g., 0.044"+) allows more potential float when factory headspace is loose (common, often 0.046"–0.050"+ total).
Shallower recess enables tighter minimum headspace for precision.
Variances exist even within the same manufacturer due to tolerances (0.001"–0.005" typical).
Shimming limit: Tighten down to near the recess depth (leave 0.001"–0.002" safety clearance to avoid excessive wear on bolt face/breech or hard closing). Metal-to-metal contact risks binding or accelerated wear — never push to crush rims (slam-fire hazard).

Reported Bolt Face Rim Recess Depths (User/Gunsmith Measurements)

Compiled from forums (RimfireCentral, AccurateShooter, Sniper's Hide), videos (ELEY, Kurt the Gunsmith), and gunsmith reports. Actual values vary by rifle.

Manufacturer / Model	Reported Recess Depth	Notes / Source Highlights
CZ (general / 457)	0.040"–0.043"	ELEY video chart; RimfireCentral users; common for match setups
CZ 457	0.041"	Sniper's Hide direct measurements
CZ 455/452/453	0.040"–0.043"	Similar to 457; EnoughGun forum reports
Ruger 77/22	0.042"–0.044"	RimfireCentral multiple users; some deeper at 0.044"
Bergara B-14R	0.041"	Sniper's Hide user measurements
Tikka T1x	0.040"–0.043"	CanadianGunNutz forum reports
Anschutz (e.g., 54)	0.040"–0.042"	RimfireCentral; low variance in match rifles
Vudoo V-22 (custom)	~0.041"	Designed precision; Vudoo reviews
Lithgow LA101	~0.041"	EnoughGun forum (similar to CZ/Tikka)
General Factory Range	0.038"–0.045"	SAAMI allows headspace 0.043"–0.051"; recess supports rim without excess play

How to Measure Bolt Face Rim Recess Depth

Tools: Depth micrometer (0.001" accuracy preferred) or digital calipers with depth gauge. Remove bolt from rifle.
Prep: Clean bolt face thoroughly. Retract/remove firing pin if possible to avoid interference.
Measure: Place micrometer base flat on outer raised bolt face (around recess). Extend probe into recess bottom (flat rim seat area, avoiding firing pin hole/extractor cuts). Read depth. Average multiple points.
Verify: Compare to ammo rim thickness (measure 5–10 rounds). Recess should be ≥ rim thickness for safe chambering. If deeper, excess float possible — shim to tighten.
Safety: Measure with bolt locked if possible for context. Use feeler gauges if no micrometer (carefully).

Real-World Examples: Shimming to Optimal Headspace

Example 1: Ruger 77/22 with 0.044" Recess
Many factory Rugers have total headspace >0.046"–0.050" (excess beyond recess). Shim forward until outer ring is just shy of breech (leave ~0.001"–0.002" clearance for safety/avoid excessive wear or hard closing), resulting in headspace around 0.045" (or slightly more depending on tolerances). This removes factory slop, improving consistency for thin-rim match ammo while safely handling thicker rims like CCI (~0.043") with minimal positive clearance. Further tightening below 0.044" requires machining.

Example 2: Bergara B-14R and CZ 457 with 0.041" Recess
Both rifles often measure ~0.041" recess depth (per user reports on Sniper's Hide and RimfireCentral). Factory headspace may be 0.045"+ (excess float). Using bolt shims (e.g., 0.001"–0.002" from TriggerShims.com), advance the bolt forward to achieve a final headspace of ~0.042" (sweet spot for Lapua/SK ~0.041" rims or slightly thinner Eley). This minimizes rim slop for uniform primer strikes and tighter groups, while maintaining safe clearance (no crush risk on 0.043" rims). The recess floor prevents going below ~0.041" without machining — shims simply remove excess above it.

Dial in your rifle safely!
Visit TriggerShims.com for bolt shims (precision 304 stainless, color-coded, 100% American-made in Michigan). Free economy shipping on orders — proudly the world's largest gun shim manufacturer.

Questions? Call/text Lance at 517-499-5366 or email Lance@TriggerShims.com. We appreciate your patronage — God Bless the U.S.A.!

All Material Copyright of Lance Shively 2008 ~ 2026 and Beyond
Developed with research assistance from xAI and Grok

V1.1

BOX# Bolt Shim Reviews

TECH TIP: Bolt Shim Reviews

Isaiah 5:20 Woe unto them that call evil good, and good evil; that put darkness for light, and light for darkness; that put bitter for sweet, and sweet for bitter!

Good Morning Lance,
Another testimonial from a very happy customer. As previously mentioned, I was having failure to extract issues with my CZ457 with a custom ibi barrel. At first I considered that I potentially had a very close tolerance chamber, (which I do - cut with EleyEPS reamer), that was specific for only some types of ammunition. Or perhaps there were imperfections present that interfered with extraction(?). But given the fact that extraction was 100% with some ammo, and dropped to 60-70% with others, led me to measuring rim thickness. There was a consistent difference of 0.002 to 0.003 difference. Bit of a “Aha!” moment. Perhaps there was a bolt/extractor engagement issue. After visiting several websites, chat rooms, etc. I went back to ibi to confirm that I was on the right track. Excellent customer service from these folks, and a subsequent email confirmation that I was on the right path was received. They also list Triggershims.com as the go-to for quality products related to bolt or barrel shims. I visited your site, read other folks reviews and committed to giving the bolt shimming process a try. Following the suggested trial/error fitting procedure, I was up to .007 before I noticed a definite resistance on closing the bolt. Backed off and refitted with shims totalling .0065. Resistance was less and it was time to go to the range for confirmation. Priority one was to determine if the ammunition that I was having major extraction issues with would actually cycle properly. Not one failure out of the first 10 rounds. However, I did note a stiff bolt closure on some cartridges Again, following your direction provided on your site, I backed off to .005 and tried again. Fired a full 100 rounds without one failure! Bolt engagement feels just fine. What a revelation! It would be an understatement to say I’m extremely happy with the result. Your shims are an easy install on the CZ457, and allows me to return to one of my favourite ammunition lines with confidence. Thank you again for making such a great product. Believe I will order another set, just in case lol!
Kindest Regards ~ Stephen in BC

Customer Mike from PA Writes:
Lance, just a note to share the joy :-) your shims in my CZ 457 AT-ONE cut my groups (5 groups of 5 shots including cold bore shot) from 4 inch total of all five groups to 2.065 total of all five groups, almost in half. The CZ needed .007" of shims. It was little hard to open the bolt after firing so I backed down to 006, using a 004 and 002. Still shot a 7/16, a 5/16, a 3/8, a 7/16, a 5/8. Than I put 9 shots in 9/16 at 50 yds. I used to be sure of a 3/4 inch group, with an few 1/2 inch groups. I can't wait to see what I get at 100 yds and 150yds ~ Thank you for your product!

https://kurtthegunsmith.com/

~ Gunsmithing Journal ~

CZ-457 Accuracy:
The Most Affordable Way to Accurize Your CZ

An In-Depth Article in a Prominent Gunsmithing Journal about Bolt Shims
~ Click Photo to Open CZ-457 Accuracy in a New Tab ~

Quote from Kurt's Article ~ How Bolt Shims Work to Improve CZ-457 Accuracy
"It is no secret that headspace plays a huge role in rifle accuracy. On rimmed cartridges, such as the 17 HMR, .22 LR, and 22 Mag, the headspace is measured off the thickness of the cartridge rim. The tighter the headspace, the more consistent the cartridge will be positioned in the chamber, and the more consistent it will ignite the powder. Accuracy is a direct by-product of consistency and repeatability."

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We Cheerfully accept Cash, Money Order, and Credit Cards through our Secure PayPal Check-Out

All Website Orders are Shipped the Next Business Day

I will Ship Shims to USA, Canada and International

Gun Parts Shipped to USA Only

"American Made Gun Shims" - GunShims.com - TriggerShims.com
and
TriggerShims is a Trademark
of
Shively Sales
Michigan Center, Michigan

All Material Copyright of Lance Shively
2008 ~ 2025

God Bless and Make America Great Again!

BY PURCHASING SHIVELY SALES PRODUCTS
YOU ASSUME ALL RESPONSIBILITY FOR THEIR SAFE INSTALLATION AND USAGE.
YOU RETAIN ANY AND ALL RESPONSIBILITY FOR YOUR OWN ACTIONS. Be Safe!!

If you have any questions or safety concerns, see a qualified Gunsmith.

I manage this site myself, Please Report Any Website Problems to;
Lance at Webmaster@TriggerShims.com

I Reserve the Right to Refuse Service to Anyone

Republic.... I like the sound of the word. It means people can live free, talk free, go or come, buy or sell, be drunk or sober, however they choose. Some words give you a feeling. Republic is one of those words that makes me tight in the throat - the same tightness a man gets when his baby takes his first step or his first baby shaves and makes his first sound as a man. Some words can give you a feeling that makes your heart warm. Republic is one of those words. - John Wayne in the Alamo

TriggerShims.Com

👈 Index Left Side of Page

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I Will Defend Our Right to Keep and Bear Arms ~ Donald John Trump

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TriggerShimsBolt Shim Page

Rebellion Against Tyrants is Obedience to God ~ Benjamin Franklin ~

Manufacturer of Trigger Shims Brand American Made Gun Shims - Home of - TriggerShims.com GunShims.com ShivelySales.com MichiganCenterOutdoors SmallShims.com

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PAGE INDEX

Bolt Shim Index

~ Quick Links to Items on This Page ~

Bolt Shims: Economical Headspace Adjustment for Rimfire Rifles

Index for Bolt Shims on Our Website

Rimfire Rifle Bolt Shim Index

BoltShim-INDEX 9/24

Our Ever Expanding Selection of Rimfire Rifle Bolt Shims

Links to Our List of .22 Rifle Bolt and Barrel Shims

~ Barrel Shims ~

Index for Bolt Shim Sizes

V2.2-BOX~BS-SIZES 8/25

Selection of Rimfire Rifle Bolt Shims Sorted by Size

Review

Bolt Shim Instructions

LANCE'S TECH TIP:Rimfire Bolt Shim Installation~ A General Guide ~

TriggerShims.com Shim Thickness Color Code

TriggerShims Bolt Shim Instructions Copyright 2008 - 2025 V7/2025

Tech Tip: Rimfire Headspace

Lance's Tech Tip: Match Chamber and Rimfire Headspace

V10/2024

Headspace Tech Tip

Headspace Tech Tip

Headspace Tech Tip V1.1

TECH TIP: CZ Rimfire Headspace Tuning for Maximum Accuracy (Bolt & Barrel Shims – All Models)

Optimal Headspace Recommendation (All CZ Models)

Step-by-Step: Measuring & Adjusting Headspace on CZ Rifles

Dial in your CZ rifle today — American-made precision starts here!

Popular Rim Thicknesses Quick Reference

All Material Copyright of Lance Shively 2008 ~ 2026 and Beyond Developed with research assistance from xAI and Grok

V1.1 - 02/25/2026

Bolt Face Tech Tip

TECH TIP: Bolt Face Rim Recess Depth and Its Effect on Shimmed Headspacing

Why Recess Depth Matters

Reported Bolt Face Rim Recess Depths (User/Gunsmith Measurements)

How to Measure Bolt Face Rim Recess Depth

Real-World Examples: Shimming to Optimal Headspace

All Material Copyright of Lance Shively 2008 ~ 2026 and Beyond Developed with research assistance from xAI and Grok

V1.1

BOX# Bolt Shim Reviews

TECH TIP: Bolt Shim Reviews

https://kurtthegunsmith.com/

~ Gunsmithing Journal ~

CZ-457 Accuracy: The Most Affordable Way to Accurize Your CZ

UPGRADE FROM FREE ECONONY SHIPPING ~to~ SHIM TRACKING w/ SHIPPING PROTECTION #ESU

~ SHIMS ONLY ~ ~ $6.00 U.S. Tracking UPGRADE ~

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I Reserve the Right to Refuse Service to Anyone

I Will Defend Our Right to Keep and Bear Arms
~ Donald John Trump

TriggerShims
Bolt Shim Page

Rebellion Against Tyrants is Obedience to God
~ Benjamin Franklin ~

Manufacturer of
Trigger Shims Brand
American Made Gun Shims
- Home of -
TriggerShims.com
GunShims.com
ShivelySales.com
MichiganCenterOutdoors
SmallShims.com

LANCE'S TECH TIP:
Rimfire Bolt Shim Installation
~ A General Guide ~

All Material Copyright of Lance Shively 2008 ~ 2026 and Beyond
Developed with research assistance from xAI and Grok

All Material Copyright of Lance Shively 2008 ~ 2026 and Beyond
Developed with research assistance from xAI and Grok

CZ-457 Accuracy:
The Most Affordable Way to Accurize Your CZ

~ SHIMS ONLY ~
~ $6.00 U.S. Tracking UPGRADE ~

NOW Includes
~ SHIPPING PROTECTION* ~
~ USA ONLY ~

Upgrade from FREE ECONOMY MAIL to
Bubble Pak w/ Tracking