Rifle's with a fat chamber.

[ShadeTree]

My Rem 788 308 seems like it might have a slightly oversized chamber. I had around 15 or so once fired factory 308 cases that I used in my initial testing with it. All through them now and when I go to resize it's a tight squeeze. Just bumping the shoulder .002 still makes the brass grow .010-.015. Thought it was possibly the die, but I have a RCBS and also a new Lyman I picked up at a yard sale some time back, and both are about identical difficulty on resizing. Is going to be tough on brass at that rate.

What's the solution there as far as dies?? Call RCBS or Lee and send them a fired case and get them to make a die for the chamber? How do you guys do it when running into something like that?

 

[MZ5]

Maybe you need better case lube? Dies with a smoother interior finish?

A Lee collett die avoids the issue in the short term. A Redding bushing bump die or similar _may_ allow you to bump the shoulder back without squeezing down the whole body of the case. Not sure that's quite what you're looking for, though(?).

Sure, call the die makers to ask whether they can (and are willing to) do what you want, which is to match the dies to your rifle's chamber. Personally, I wouldn't spend the hundreds of dollars I expect that to cost. I can anneal or even replace a lot of brass for that kind of money, and I can replace the barrel for not TOO much more.

When chamber reamers get dull, the chambers they cut are more over-sized. I have two rifles from the same manufacturer chambered for the same cartridge. The one was clearly cut with a new or very nearly new reamer. That chamber is not much larger than my Redding body die at all. It's great! The other was clearly one of the last rifles chambered before they sharpened or replaced the reamer. The brass is significantly larger after firing from that rifle than from the first one. It's irritating, but there's nothing for me to do about it (that I'm even remotely willing to do). I normally only neck size anyway, so the only real challenge for me is keeping the fired brass separate so that I don't have a failure to chamber in the field with the one rifle. I body size (and anneal) when I need to, not just because I fired the cartridge.

 

[ShadeTree]

Not likely the case lube as I've done thousand's of others using it without issue. The cases come out of the dies normal on the return stroke, just takes extra pressure on the press handle to get them squeezed down initially. 2 dies that exhibit the same difficulty in initial sizing and cases that are growing up to .015 when only bumping the shoulder .002, makes me think it's a fat chamber.

Hadn't really thought about a Lee collet die...........don't know why. That would be an option, however most times they still need run through a FL sizer after a couple loads. I was thinking Lee made custom dies for not a lot of money, but I might be mistaken about that.

 

[hunter24605]

Lee still does it, I think. It was around $250 for a 3 die set and they asked for 4 or 5 fired cases. Don’t know about just a sizing die.

 

[ShadeTree]

Lee still does it, I think. It was around $250 for a 3 die set and they asked for 4 or 5 fired cases. Don’t know about just a sizing die.

Yikes. Well that's out. Not saying they're overcharging, just I wouldn't spend that. Maybe do the Lee collet neck sizing die and resize when necessary and live with it. Or just blow threw brass in 4-5 reloads and live with it. It's not a bench rifle that I'm planning on putting 1500 rounds with it down range.

 

[jimbires]

I don't have any fat chambers . I'll guess a custom die is the best answer , depending on cost . sizing brass is like squeezing a water balloon . when you squeeze the sides it gets longer . so you are correct in thinking you're over working the brass . you are also correct on the neck die , you will need to size the body after a couple of fires . I "THINK" it's whidden that has ( I'll call them ) semi custom dies . you send them some fired brass , and they send you their best match die . if you decide to go this route , I'd ask them if you should neck size only the brass a couple times until it gets tight to chamber , this would be fully expanded brass .

 

[hunter24605]

Yikes. Well that's out. Not saying they're overcharging, just I wouldn't spend that. Maybe do the Lee collet neck sizing die and resize when necessary and live with it. Or just blow threw brass in 4-5 reloads and live with it. It's not a bench rifle that I'm planning on putting 1500 rounds with it down range.

Luckily you can fall of a stump and land on good 308 brass

 

[ShadeTree]

I don't have any fat chambers . I'll guess a custom die is the best answer , depending on cost . sizing brass is like squeezing a water balloon . when you squeeze the sides it gets longer . so you are correct in thinking you're over working the brass . you are also correct on the neck die , you will need to size the body after a couple of fires . I "THINK" it's whidden that has ( I'll call them ) semi custom dies . you send them some fired brass , and they send you their best match die . if you decide to go this route , I'd ask them if you should neck size only the brass a couple times until it gets tight to chamber , this would be fully expanded brass .

My Dad's 348 I have here is the same way as far as making brass grow on resizing, although I'm not convinced at all that is due to a fat chamber, but rather the heavy taper in that case that makes them feed like greased snot.

I set the die up to headspace off the shoulder instead of the rim, about .003. Doing it that way certainly doesn't hurt accuracy and minimizes the case stretch on resizing. Then at around 3 loadings I hit it with a full length resize otherwise it will start getting tight because setting the die up high like that doesn't get the base of the case sized down, much like neck sizing only. I get good case life out of it that way, but otherwise a 348 can be pretty poor on case life.

 

[NYDAN]

My Rem 788 308 seems like it might have a slightly oversized chamber. I had around 15 or so once fired factory 308 cases that I used in my initial testing with it. All through them now and when I go to resize it's a tight squeeze. Just bumping the shoulder .002 still makes the brass grow .010-.015. Thought it was possibly the die, but I have a RCBS and also a new Lyman I picked up at a yard sale some time back, and both are about identical difficulty on resizing. Is going to be tough on brass at that rate.

What's the solution there as far as dies?? Call RCBS or Lee and send them a fired case and get them to make a die for the chamber? How do you guys do it when running into something like that?

I have had rifles with a "fat" chamber. They are a pain in the rear. Another issue you may experience with a "fat" chamber may include getting the donut ring at the base of the neck. The thicker shoulder material gets worked up into the neck.

 

[ShadeTree]

Luckily you can fall of a stump and land on good 308 brass

 

[ShadeTree]

I did have an RCBS die that was undersized and did that to brass.......hard to resize with and made the brass grow more than normal. I knew it was the die because I checked it against my buddies RCBS die, and also a Pacific die I had here and neither of those did that. It was an OLD die, sent it to RCBS and the tech checked it out and sure enough it was slightly undersized. They sent me a new die free of charge. Good folks to deal with that way.

I've no way to prove otherwise, but with 2 dies here both doing the same thing, it's hard to believe that both are undersized. Almost certainly has to be the chamber. Be a big problem on a high dollar rifle. A 788 used for hunting that shoots good.....I guess not that big of a deal in the big picture.

 

[RL338]

The way I do it , get yourself a Redding body die and a Lee collet die. 2 step process , but it should slow down your growing issue.

 

[Johnly]

If I saw cases grow that much, the first thing I would think of would be a headspace issue.
How easy do the fired cases chamber? How pronounced is the swell forward of the extractor groove?
The first thing I would suggest would be to neck size the cases and see how easily neck sized loaded round chamber in your rifle.

 

[jimbires]

My Dad's 348 I have here is the same way as far as making brass grow on resizing, although I'm not convinced at all that is due to a fat chamber, but rather the heavy taper in that case that makes them feed like greased snot.

I set the die up to headspace off the shoulder instead of the rim, about .003. Doing it that way certainly doesn't hurt accuracy and minimizes the case stretch on resizing. Then at around 3 loadings I hit it with a full length resize otherwise it will start getting tight because setting the die up high like that doesn't get the base of the case sized down, much like neck sizing only. I get good case life out of it that way, but otherwise a 348 can be pretty poor on case life.

have you tried to fire the brass a couple times with neck sizing only until it gets tight to chamber , then set your full length die to push the shoulder back .002 or .003 ? if the full length die is set up on brass that is not fully expanded , it could cause you problems . another thing is , I had trouble getting consistent shoulder length measurements after sizing , when I was setting my die up with a gap between the die and shellholder . I bought a set of the Redding competition shellholder sets , it fix my problem . I now have these shellholder sets for everything I load . I get very consistent measurements now . just a couple of thoughts .

 

[ShadeTree]

If I saw cases grow that much, the first thing I would think of would be a headspace issue.
How easy do the fired cases chamber? How pronounced is the swell forward of the extractor groove?
The first thing I would suggest would be to neck size the cases and see how easily neck sized loaded round chamber in your rifle.

It's growing in length on resizing only with a shoulder bump of only .002. Not a headspace issue. But it wouldn't matter if it had a severe headspace, if the die is set to only bump .002, on resizing, your brass should grow very little. That's the point of that, you're not pushing the brass all the way back to factory specs every sizing. But it doesn't have loose headspace, the die is just off of all the way down to get that .002 on fired cases. The worst tightness with both dies is at the start and center of the case not at the base. Fired cases both extract and rechamber fine.

 

[ShadeTree]

have you tried to fire the brass a couple times with neck sizing only until it gets tight to chamber , then set your full length die to push the shoulder back .002 or .003 ? if the full length die is set up on brass that is not fully expanded , it could cause you problems . another thing is , I had trouble getting consistent shoulder length measurements after sizing , when I was setting my die up with a gap between the die and shellholder . I bought a set of the Redding competition shellholder sets , it fix my problem . I now have these shellholder sets for everything I load . I get very consistent measurements now . just a couple of thoughts .

No I don't have a neck sizing die for it. It seems to work out fine this way really. It is after all a lever gun and I'm shooting it open sights and get about as good as accuracy out of it as I can shooting without a peep sight. My main thing was to do what I could to help brass life out and it does seem to do that without negatively affecting accuracy.

 

[jimbires]

I wasn't thinking . everything I've messed with for a long time are bolt guns . yes , you have to be careful with lever and pump guns . if you don't size the brass enough they can be hard to chamber .

 

[ShadeTree]

I wasn't thinking . everything I've messed with for a long time are bolt guns . yes , you have to be careful with lever and pump guns . if you don't size the brass enough they can be hard to chamber .

 

[ShadeTree]

The way I do it , get yourself a Redding body die and a Lee collet die. 2 step process , but it should slow down your growing issue.

RL, I was on the road this evening going to pick up some equipment and was thinking of this very thing........a Redding body die. Never used one. But wouldn't that die also need to be oversized or else I'd still be squeezing the case body back down same as the full length die?

 

[RL338]

My 7400 is a little sloppy to. Fired brass out of my 7400 I measurer 0.456” diameter at the shoulder and 0.469” at the base. My S2 308 measures 0.454” diameter at the shoulder and 0.469” at the base.
Yes the body will size down like a FL. My 7400 I body size every other firing. If I was loading your rifle I would Lee Collet Die until a fire case wouldn’t chamber then body size it.