rimfire chamber depth

S

skeetlee

Active member
Hey fellas. I have been absent for a while. My little rifle shop has grown into something I would have never guessed. I couldn't be any more pleased. With this said, I am venturing out a bit. The rimfire world has my attention. Centerfire is my bread and butter and I assume it will always be. The rimfire at this point is nothing more than interesting me.
I am gonna build myself a rifle here pretty quick and I have a few questions? This wont be my first rimfire chamber, I have cut a few and they always seem to shoot well.
what I am wanting to get a better grasp on is the chamber depth. How does one really know where you wanna end up? I have just been reaming deep enough that I get good contact with the rifling on the driving band of the bullet. To be honest I am guessing a bit? I am wanting to build a depth gauge so I can record my depths. Any suggestions as to what angle I should cut on the front of my depth gauge or plug gauge? I think a simple plug gauge that I can insert and then record a measurement off the back of to the breach face should tell me what I need to know. I am open to suggestions of course.
I hope all has been well for you fellas. I apologize I haven't participated in a while. The shop is busy and I haven't shot a match since I know when. I owe a lot to the people here and I am always appreciate of the info shared. thanks Lee
 
Not to be a dork but (OK, too late... I AM a dork but...) isn't this kindofa' rimfire question? I mean there's a whole nuther group of guys over there, it's like they live in a different world or something. I've only entered their domain a few times in many years and first thing I notice is "I DON'T KNOW ANYBODY HERE!"

Next I notice "it's hard to see in here" . . . .

but ennyways

Maybe at least try it ..... they are serious ......... just very little crossover.
 
2 popular engraving depths are .090 or .030. This would be .130 or .070 measured from the back of the barrel to the back of the rim.
 
This has a fair number of variables.
Are you cutting a full on match chamber ? There are several opinions starting with what ammo will be primarily shot.
Assuming you’re cutting a 1.5-2 deg. leade a lot of very good chambers are cut to engrave about 1/2 the drive band on ELEY. Some cut to engrave the first 1/4 . Be very aware that if you cut for, say ELEY you want to be careful about engraving the entire slug.....from lot to lot you can have variance of .008” , so you don’t want the whole process to be driven off a short lot.
Some guys chamber for ELEY, some for Lapua, but a well cut chamber engraving 1/2 an ELEY slug should serve you well.
I’m assuming you're going with a 4 or 6 groove barrel. If it’s a 2 or 3-then some guys do them with a boring bar( or two) to avoid reamer deflection, but that’s a whole other rabbit hole to go down.
You do know most CF guys won’t touch a .22 BR job, don’t you:(
 
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Having a hand full of variables to learn doesnt scare me away from learning something new in my shop. If fact I welcome the knowledge and challenge.
My barrel for my project is a shilen ratchet . I think I'll use my jgs match reamer. I plan to use eley as I can buy eley at a dealer discounted price.
Thanks for the info. I always appreciate it. Lee
 
If you haven't already, take a look at Jerry Stiller's Rimfire Accuracy Forum. He has a thread about what it takes to get to the top and I just bumped a thread on barrel chambering. Some of the best rimfire smiths in the country have posted over there. Opinions do differ, but for a modern rimfire benchrest action, most seem to like somewhere around .130 to .140 stickout from the back of the barrel to the head of the case.
 
skeetlee said:
Having a hand full of variables to learn doesnt scare me away from learning something new in my shop. If fact I welcome the knowledge and challenge.
My barrel for my project is a shilen ratchet . I think I'll use my jgs match reamer. I plan to use eley as I can buy eley at a dealer discounted price.
Thanks for the info. I always appreciate it. Lee
Click to expand...

I would add a final thought, you may even wish to try a few variations on cutting lubricant, another hot topic.
Remember any slight burr, etc. on a PPC chamber will shoot off fairly quickly.
That ain't happening with a 22. Some guys can cut/ bore a heel of a chamber, some even do a post chamber light lapping. Pretty hard to cut a great chamber with that little hole.....good luck.
 
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