Helpful Hint - Case Length

[K22]

This is not something that is new - it's but posted on here before but often buried in posts about trimming. So, I thought it might be helpful to create a separate post on this helpful hint to give it more visibility since it has really made a difference for me.

As every reloader knows, maintaining case length so the case is not jammed into the chamber is an important safety, functionality, and accuracy issue. Trimming cases, while a necessary pain, is nevertheless required when this length exceeds chamber length. Most reloaders follow SAMMI specs as a guide on chamber length and when to trim. For many factory rifles, this SAMMI spec dimension is considerably shorter than the actual chamber length.

Sinclair markets a simple, inexpensive, easy to use tool, a chamber length gauge, which allow you to measure the actual chamber length of your rifle. Even applying their specified safety factor, which is a must, I've been able to reduce the amount of trimming needed by over 75%.

There is even some that claim that by not trimming shorter than necessary that this reduces the chances of carbon ring formation. I don't know if that is true, but it does seem logically.

Anyway, I just wanted to pass this along to you guys especially those who hate trimming cases as much as me. 

PS: My aftermarket, custom Douglas and Hart barrels do have short chamber lengths that are very close so SAMMI specs so this may not apply to all rifles. Also, my Browning X bolt factory rifles are also fairly close to SAMMI specs for chamber length. The only way to know is to measure each rifle before applying any trimming adjustment to SAMMI specs.

 

[Diverjeff]

I used the Sinclair gauge on my CA MPR 338LM and found my chamber length was considerably longer than SAAMI spec. Will keep my cases trimmed .005"-.010" shorter than my chamber length and like you mentioned should help cut down on carbon ring thickness.

 

[Clancy]

I hated trimming cases… but once I got a WFT, it’s been easier to deal with.

I’ll still look into the gauge. Thanks.

 

[brokeasajoke]

How to Craft Your Own Chamber Length Gauge « Daily Bulletin

We are sad to report that long-time Forum member Frank S. (aka fdShuster) passed away in 2015. 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...

bulletin.accurateshooter.com

Thought I'd share this.

 

[markm87]

I used to be fanatical about trimming, but now I almost NEVER trim brass anymore (except .223 since it's mixed and I have a Giraud). I'm not competing, mind you. I'd guess that every few years I'll get out the trimmer and even out a few hundred pieces of brass, and then put it back on the shelf to gather dust.

It might not be a bad idea for me to get back into trimming now that we shoot a lot of 6.5cm. Usually the primer pockets are smoked before trimming enters my mind though.

 

[Rocketvapor]

You can check chamber length with a couple cases (short and long) with a borescope. Little red dots in picture show the end of the case. Looks like anything less than 1.775" would not be a problem and still allow a couple thou for stretch.

 

[Chubbs]

How to Craft Your Own Chamber Length Gauge « Daily Bulletin

We are sad to report that long-time Forum member Frank S. (aka fdShuster) passed away in 2015. 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...

bulletin.accurateshooter.com

Thought I'd share this.

I tried that a while ago and the ring came of in the chamber. I can't begin to explain how much fun it was getting it out.

 

[Coyotefurharvester]

I use the borescope also to check chamber/brass length.

 

[PhilC]

I've used the Sinclair "plugs" for decades, all of my rifles have their own unique trim lengths which are .010" less than the "as cut" chamber length.

 

[K22]

How to Craft Your Own Chamber Length Gauge « Daily Bulletin

We are sad to report that long-time Forum member Frank S. (aka fdShuster) passed away in 2015. 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...

bulletin.accurateshooter.com

Thought I'd share this.

I knew Frank, shot on the club pistol team with him in the 80's in western PA. Really nice guy and very knowledgeable. I was 90% a pistol shooter in those days so I didn't reap from his knowledge of rifle shooting.

 

[Tesoro]

Thankyou very much. I just found yet another gadget to order off brownells!

 

[sqrlgtr]

Just be aware if you are going to get the sinclair plugs and use them on a tight neck chamber you will have to turn the plug down for your specific neck dimension....

 

[sqrlgtr]

Forgot to mention this is another good use of the teslong bore scope you can see exactly where the case mouth ends in your chamber....

just seeen above someone (rocketvapor) had already mentioned the use of a bore scope

 

[divingin]

Another method (for 6mm cartridges) is the use of a 22 Magnum case in place of a bullet, used with the Hornady Stony Point headspace gauge. You need to chuck the 22Mag case up in a drill and turn it down to something less than your chamber neck diameter (I'm sure there are other ways, but I just used a jewelers file. I also hit the flat of the case head as well to square it up a bit.) Slip the 22Mag into a scrap case that has the neck shortened (to allow room for the remaining 22 Mag rim), and use the rod on Hornady to shove it up against the front of the chamber, Pull everything out and measure your max brass length. Sounds a lot more involved than it actually is.