November 1st, 2016

Measure Your Chamber Length with Home-Made Modified Case

do it yourself chamber length gauge Sinclair case neck

We are sad to report that long-time Forum member Frank S. (aka fdShuster) passed away last year. Frank was a very knowledgeable shooter who was always willing to help others. Here is one of Frank’s smart inventions. He devised a way to measure the length of a rifle’s chamber using a fired cartridge case. This lets you find your MAX trim-to-length for any chamber. Frank’s system works by cutting a “collar” from part of the case neck. This then slips over a bullet seated in a case loaded without powder or primer. As you chamber the dummy round, the collar will move back to indicate the full length of the chamber. (Make sure the bullet is seated well off the lands so the dummy round can chamber fully.)

do it yourself chamber length gauge Sinclair case neck

do it yourself chamber length gauge Sinclair case neck

The pictured gauge can be home made (for free) with components you already have on hand. Frank explained: “I used a Dremel cut-off wheel to cut the front half of the case neck off. A jewelers needle file to de-burr both rough-cut edges. The cut-off surface does not need to be perfectly square, because you are using the original straight mouth to make contact at the front of the chamber. Seat any old bullet to the approximate normal seating length. Next apply a tiny drop of oil on the ogive of the bullet, and slide the ‘collar’ over the bullet. Then chamber the dummy round and close the bolt. Extract the round slowly and carefully and take the measurement with calipers (see top photo).”

Frank’s DIY chamber length gauge works well. In a related Forum thread, Frank posted: “I’ve compared length dimensions doing it this way and with the chamber length shown on my chambering reamer drawings, and the Sinclair gauge, and they are all within .001″ or so.”

do it yourself chamber length gauge Sinclair case neckCommercial Chamber Length Gauges May Not Work with Custom Chambers

Frank did use Sinclair chamber-length gauges for some applications. These bullet-shaped gauges slip into a cartridge, but “it’s inconvenient to order that little gauge only… without spending $6 shipping for a $7 item.” Moreover, the Sinclair gauges may not fit a custom chamber with a tighter neck dimension because the diameter of the ring at the end is too large.

As an alternative to commercial gauges, the collar-type, homemade gauge will function properly in a custom chamber. The homemade gauge will work with smaller-than-standard chamber neck dimensions, as long as you use a piece of appropriately-turned fired brass that fits your chamber.

Permalink Reloading, Tech Tip 4 Comments »
July 15th, 2015

NEW Lyman Ammo Checker Multi-Caliber Case Gauges

Accurateshooter.com Lyman case gauge Ammo Checker CNC Reloading

Here’s a handy new item, particularly if you load large quantities of bulk ammo for a variety of firearms. Lyman’s new Ammo Checkers check the diameters of reloaded rounds and factory ammo, so you can quickly confirm that your ammo fits a standard chamber. Just drop your loaded rounds in the Ammo Checker, and if the round fits into the gauge, it will fit in the gun’s chamber.

Lyman Ammo Checkers are multi-caliber — each orange block checks six or eight different cartridge types, with each caliber/cartridge name engraved on the gauge. Ammo Checkers are machined to SAAMI minimum chamber dimensions from solid blocks of 6061 T6 aluminum. Ammo Checkers are available in three versions covering most common handgun and rifle calibers:

Handgun Ammo Checker (#7833000) MSRP: $29.95
Fits: 380 Auto, 9mm Luger, 38 Super, 40 S&W, 45 ACP, 38/357, 44 Spl/Mag, and 45 Colt

Small Rifle Ammo Checker (#7832321) MSRP: $39.95
Fits: .204 Ruger, 22 Hornet, .223 Rem, 22-250, 300 AAC Blackout, 7.62×39

Large Rifle Ammo Checker (#7833002) MSRP: $39.95
Fits: .243 Win, .270 Win, 30-30 Win, .308 Win, .30-06, 300 WSM

Why Use a Case Gauge?
We find that case gauges like the Lyman Ammo Checker are particularly useful for handgun reloaders using progressive presses. The chambers of many popular semi-auto pistols are partly unsupported. This allows the case to swell in the bottom quarter. The case may not be sized adequately by your sizing die, which can lead to misfeeds or malfunctions.

Additionally, if you have loaded a large quantity of ammo for a semi-auto rifle such as an AR15, it’s not a bad idea to check your cartridges before you load them into your magazines. All you need is one mis-sized round to cause a stoppage. That will ruin your day if you are competing in a Service Rifle match or 3-Gun event.

Permalink Handguns, New Product, Reloading 1 Comment »