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March 4th, 2021

Shoulder Bump — Five Cool Tools to Measure Your Bump

shoulder bump headspace gauge comparator tool whidden manson

The Tactical Rifle Shooters Facebook Group recently showcased tools used to measure case headspace before and after “bumping” the shoulder. After a case is fired, hand-loaders who full-length size their cases will typically bump the shoulders back anywhere from .001″ to .0035″, depending on the rifle and application. With our 6mmBR and Dasher cases we like about .0015″ bump.

You want the amount of case sizing and bump to be the same for all your brass. To ensure uniformity, it makes sense to measure your cases before and after the FL sizing process. When we have time, we check every case. Other folks will simply check the first 3-4 cases coming out of the FL sizing die to ensure the FL die setting is correct and delivering desired headspace/bump.

1. Whidden Gunworks Shoulder Bump Gauge

shoulder bump headspace gauge comparator tool whidden manson

There are a variety of tools that can be used to measure shoulder bump. Our favorite is a special cartridge-specific bushing made by Whidden Gunworks. The Whidden Shoulder Bump Gauge enables you to adjust your sizing die to the desired measurement. The bump gauge is attached to your calipers with a set screw and determines the measurement from the base to the shoulder of the case. The photo below, from Tactical Rifle Shooters, shows the Whidden Bump Gauge for the .375 CheyTac cartridge.

2. Dave Manson Vertical Comparator with Dial Read-Out

shoulder bump headspace gauge comparator tool whidden manson
Background image courtesy Tactical Rifle Shooters; inset photo from Manson Precison Reamers.

Dave Manson states: “This tool was designed to make life easier for the advanced shooter and re-loader by allowing precise measurement of ammunition, case, and chamber headspace. With this information, the re-loader will be able to fine-tune clearances and fits between his ammunition and chamber, with resultant improvements in accuracy and case life.” The functions of the Manson Comparator are:

1. Measure headspace of factory or reloaded ammunition
2. Quantify chamber headspace by measuring headspace of a fired case
3. Ensure minimal shoulder set-back when setting up re-loading dies
4. Compare base-to-ogive length to ensure consistent bullet-to-rifling relationship.

In addition to the Dial Indicator and Stand, the $130.00 Vertical Comparator is supplied with multiple Datum Blocks of precise length and inside diameter (.3300″/.3750″/.4000″/.4375″). MORE INFO HERE — Catalog page 20.

3. Hornady L-N-L Headspace Comparator System

shoulder bump headspace gauge comparator tool whidden manson

Hornady’s Lock-N-Load Headspace Comparator system is easy-to-use and handy. You can get a kit with Red bushing-holder body and 5 bushings for $40.12. Hornady explains: “The Lock-N-Load® Headspace Comparator… gauge measures variations in brass before and after firing or re-sizing. It allows for headspace comparison between fire-formed brass and re-sized brass.” IMPORTANT: Hornady states: “To determine the proper bushing diameter for your cartridge, simply add the neck diameter and the shoulder diameter and divide that number by two. Use the bushing closest to that number.” Hornady offers five: .330″, .350″, .375″, .400″, and .420″.

One tip — We have found the Hornady gauges may vary a little from unit to unit even with the same nominal size. If you have more than one gauge for the same cartridge, test each on your brass — you may then note a slight difference in your bump measurements. There is also an Anvil Base Kit that mounts to the opposite blade on the caliper. This provides a more stable surface for the base of your case.

4. L.E. Wilson Case Gage Depth Micrometer

shoulder bump headspace gauge comparator tool whidden manson

If you are looking for precise “bump” measurements without having to mess with calipers and clamp-on gauge blocks, you may want to consider the L.E. Wilson Case Gage Depth Micrometer. This takes very precise, repeatable measurements, but you need to know your starting point. The manufacturer explains: “Every reloader should know exactly how much your Full Length Sizing Die is pushing back the shoulder. With the NEW Case Gage Depth Micrometer you can do just that! It has never been easier to measure you cases headspace before and after sizing. The Depth Mic allows you to slip the micrometer perfectly over the top of the Gage with your case inserted into the Gage and take a measurement. Micrometer has graduations of .001″. The Case Gage Depth Micrometer is set to a zero of .100″ on the scale at our factory. Because of differences in ‘feel’ and temperature, we include a the Gage Block for you to test Zero and to adjust if necessary.”

5. Pistol Brass Case DIY Bump Gauge

Last is a “field expedient” set-up if you do not have any of the comparator tools shown above. A sized .45 ACP case (or other suitable pistol case) can be used to measure shoulder bump. The mouth of the pistol case sits on the shoulder of your rifle cartridge brass.

Make sure the .45 ACP case is trimmed square and that it is round. We recommend you first run it through an expander, then size it, trim it and chamfer. Next, take the .45 ACP case and slip it over the neck of a fired, unsized rifle case with the primer removed. Align the two cases between the jaws of your calipers and note the length from rim to rim (See left photo below).

OK, now you have the length for a fired rifle case BEFORE sizing. Next, take a full-length sized rifle case (without primer) and do the same thing, placing the .45 ACP case over the neck of the FL-sized case (Right Photo). The difference between the two numbers is the amount of “bump” or set-back you are applying to the shoulder. Here the difference is .0015″. The amount of bump you need varies with your chamber and your load, but .0015-.002″ is a good initial setting.

Permalink - Articles, Gear Review, Reloading 2 Comments »
May 20th, 2020

Huge Memorial Day Sale at Brownells Is Underway NOW

Brownells Memorial Day Sale 2020 May

Memorial Day is just five days away, and Brownells is running a big Memorial Day Sale right now to mark the occasion. You’ll find dozens of popular products at significant discounts — up to 56% Off. Save on AR Lowers/Uppers, Triggers, Optics, Chassis Systems, Magazines, Tools, Ammo and more. If you are a black rifle fan — this is a great opportunity to pick up AR-platform components and accessories at deep discounts. But you don’t want to delay too long — Brownells Memorial Day Sale runs through 11:59 pm on Monday, May 25, 2020. And take note — inventory may be limited on some of the sale items.

Here Are Some of the Featured Sale Items

Illustrated below is just a small selection of the sale items. There are hundreds of other products on sale including: Barreled Actions, Chassis Systems, Hunting Stocks, Priming Tools, Electronic Earmuffs, Berger Bullets, Leupold Scopes, Leica Rangefinders, Lapua Ammunition, S&W .22 LR Pistols and much more.

Brownells Memorial Day Sale 2020 May

Permalink Handguns, Hot Deals, News, Optics, Reloading No Comments »
September 18th, 2018

Cool Tools for the Reloading Room — Look What UPS Brought

21st Century Tools Concentricity Checker lathe neck turner turning scale UPS

Posting on Facebook, Michael W. said: “Maybe it’s just me but I LOVE coming home to packages from the UPS driver sitting on my deck! Now I can get serious about creating some Match Grade ammunition!” Michael showed off some very impressive reloading hardware, including a 21st Century Shooting “Mini-Lathe” Neck-Turning system, 21st Century Concentricity Gauge, Shars Tube Micrometer, and the A&D FZ-120i Precision Balance. Cool Tools indeed!

21st Century Neck-Turning Lathe — A Gem
The 21st Century Neck-Turning Lathe works great — this is what we use to turn necks. It floats at both ends, so it runs very smoothly. You can use it manually or with power. It gives you very precise, clean cuts with a minimum of case lube. The cutting tool is hard and sharp so you can do large quantities of brass without having to adjust the cutter position for wear. We’ve used a half-dozen neck turners and this 21st Century Unit is our favorite.

21st Century Tools Concentricity Checker lathe neck turner turning scale UPS

21st Century Concentricity Gauge — Smart, Efficient Design
The beautifully-crafted 21st Century Concentricity Gauge is fast and easy to use yet very precise. The twin, roller-equipped case supports slide back and forth on rails so you can measure any size case, from a 17 Fireball up to a 50 BMG. The horizontal dial indicator also slides on parallel rails so you can easily measure any spot on a case or loaded round — from bullet tip (or case mouth on empty case) down to the mid-body. We like to measure run-out on our sized, empty brass on the necks and then measure again on the bullet ogive with loaded rounds. The large-diameter wheel allows bump-free, “no wobble” case rotation, delivering better results than spinning cases with your fingers.

Concentricity gauge uses stainless turning rollers for less friction and more consistent read-outs.
21st Century Tools Concentricity Checker lathe neck turner turning scale UPS

A&D Precision Balance — Ultra-Precise with No Drift
The A&D FX and FZ-series scales are magnetic force restoration balances with 0.001 gram sensitivity so they are accurate to the kernel. This balance will not drift like less advanced, load cell-based digital scales. The scale’s high sensitivity and extreme stability allow you to weigh charges and sort brass, primers, and bullets with much higher precision.

What Gadget Would YOU Like To Have Delivered?
Here’s a question for our readers… What are YOUR favorite reloading tools on currently on your bench? And if you could have the UPS driver deliver a new tool tomorrow, what would you like him to bring? A 21st Century Hydro Bullet Seater (awesome Arbor Press)? Maybe a Whidden Micro-Adjustable Sizing Die? How about the amazing Auto Trickler and Auto-Throw system from Canada? That combines a A&D FX/FZ scale with a powder thrower and microprocessor-controlled trickler. With the push of a button you get a charge dispensed and weighed to single-kernel accuracy.

Permalink Bullets, Brass, Ammo, Gear Review, Reloading 2 Comments »
October 5th, 2014

New Gun Digest Shooter’s Guide to Reloading

We recommend that all hand-loaders have a couple reliable reloading manuals as reference guides. Berger, Hornady, and Sierra all offer well-respected load manuals. These can provide starting load information for a wide variety of cartridge types and bullet selections. We do like to cross-check any printed load recipes with current online data, to ensure you have the latest info.

Along with a good load manual, those getting started in metallic cartridge reloading can benefit from a good basic reloading treatise. There’s a new intro guide from the publishers of Gun Digest.

Guide to Reloading Book

The New Gun Digest Shooter’s Guide To Reloading, by Phillip Massaro, was created for shooters new to reloading. This is a good starting point for those who want to learn to hand-load safely and efficiently. Hundreds of photos illustrate the text — and we all know a picture can be worth a thousand words.

After discussing the benefits of hand-loading, Massaro’s book covers the basics of metallic cartridge reloading, step by step. Along the way Massaro recommends appropriate presses and tools for reloading both pistol and rifle cartridges. Massaro also explains the variations in bullet and powder types, and how they affect ballistics. In addition, Massaro includes a “Specialty Situations” chapter that reveals common reloading mistakes and issues and offers practical solutions. This section on avoiding common mistakes is one of book’s best features. We wish all reloading guides had a similar section.

Editor’s NOTE: This book will be released next week. Accordingly, we have not seen the final, printed version yet. At $14.79, the Gun Digest Shooter’s Guide to Reloading is relatively inexpensive. The sample chapters we reviewed provided good basic information in a well-organized fashion. Certainly, we would not tell advanced reloaders and/or competition shooters to rush out and buy this book. However, for folks getting started in hand-loading, this resource should be helpful.

Permalink New Product, Reloading 1 Comment »
November 14th, 2009

Sinclair Bullet Sorting Assembly with Dial Caliper

Sinclair bullet ogive sorterSinclair International has a new tool assembly that lets you sort bullets by base to ogive length. The $79.95 Sinclair Bullet Sorting Stand with Dial Comparator (item 59-2000) comes with a heavy black granite base that stays put on your loading bench. The included dial indicator has a quick-release lever allowing easy placement and removal of bullets into the comparator. This lever allow the spring-loaded indicator shaft to pop up out of the way.

The special base comparators used with this tool (see photo), are sold separately for $10.99, and are offered in 22 caliber, 6mm, 6.5mm, 7mm, 30 caliber, and 338 caliber. The sorting stand can also be used with Sinclair multi-caliber hex comparators (item 09-700, $18.25).

Measuring Bullet Bearing Surface with Calipers and Comparators
While we like this Sinclair tool, the same function can be performed with a regular set of calipers, using two comparators with caliber inserts. If you use the Hornady (formerly Stoney Point) OAL system you probably already have a #B2000 comparator body and a caliber-specific insert ($3.99 at Grafs.com).

Buy a second body ($14.39 at Grafs.com) and second insert (of the same caliber) and mount one on each caliper jaw, opposite each other. Tuck the bullet’s boat-tail in one insert and the “pointy end” in the other, and you can quickly measure the bearing surface. It takes a few tries to get the right “feel” of how hard to close the caliper jaws. But if the comparator bodies are set up right, the process should be quite repeatable, and you can probably measure just as fast with calipers as with the Sinclair measuring stand. However, the Sinclair unit should be a bit more precise, if you’re trying to resolve bullet lengths to less than one-thousandth. If you want to measure base to ogive (rather than bearing surface length), just remove one comparator and measure with the heel of the bullet (end of boat-tail) touching one jaw, and the bullet’s “pointy end” in the remaining comparator.

Hornady comparator bodies

Permalink Bullets, Brass, Ammo, New Product 1 Comment »