308 Sizing problems

je2140

Sometimes I fail to resize my cases adequately and end up with rounds that only fit my 308 semi autos with loose chambers.
Any advice on how to tell if a round is seating fully in a semi auto 308 with a tight chamber (e.g. AR10) without actually firing a round?
The rounds seat well enough that the bolt looks closed, and I can't tell it's not seated until I pull the trigger and get a click.

JR
The truth is that all good modern rifles are efficient weapons; it is the man behind the gun that makes the difference

Theodore Roosevelt

JustC

you can full length resize the case with the die touching the shellholder and that should fit in anything with that chamber. Now, If you want a tighter fit, you can "partial full length" size the cases and pull the shoulder forward a few .001"s and get a much better chamber fit, but that may not be the best bet for a semi-auto.

No die can be set to perfectly size cases for multiple chambers, so you need to either use a new set of dies for each rifle, or full length sizing may be the best bet if you use one set of dies for several rifles.

Now if you want exact measurements, then the stoney point headspace tool that works with your calipers will tell you when the shoulder is still unmoved from it's fired case state, and that will allow you to set your dies to only minimally rssize the cases so that they are still a tight fit.

why chase the game when the bullet can get em from here?....
Got Balistics?

I.Shute

I use small base dies for my hunting ammo in .308, .30-06, 7mmRM, .35 Whelen and .338WM. That's what RCBS recommends for lever actions, slide actions and semi's. I use regular dies for plinking ammo and so far haven't had a failure to chamber with it, but when hunting, just don't want to take a chance with a jam.

I use only regular dies for the bolt actions.

Ray B

There are "Wilson" gauges which resemble a 308 chamber with a barely noticeable step at the head. The top of the step is the maximum length, the bottom edge is the minimum length. The idea is you drop a sized cartridge into the gauge and if the head of the case end in-between the two lengths, then it's properly sized.

Grunt2

RayB hit the nail on the head....I have gauges for just about everything I load..
I.Shute.....I have never owned or loaded for a firearm that required a short base die. In fact I prob. turn sizer dies out more often than not. Small base dies overwork the brass and are a real pain. Have you tried STD. dies in any of your semi or lever guns? You might be surprised..


"No arsenal, or no weapon in the arsenals of the world, is so formidable as the will and moral courage of free men and women.
- Ronald Reagan

I.Shute

Grunt2-
Yes, I realize that the brass gets over-worked, but with the few rounds I shoot when hunting it's not a major problem. As I said, I've never had a failure to chamber with any rifle when shooting loads loaded with regular dies, but I just want to be reasonably sure the thing's going to shoot when an animal's the target.

I'm just referring here to semi's, slide actions and lever rifles.
Never had a problem with factory loads in these either.
With bolt rifles, only use regular dies.

About the Wilson gauges? It's just one of the things I've put off getting.

I thank you and RayB for the prodding.
I'm gonna get me some.

JustC

Unless your "guage" is made to match your chamber, all you are doing is sizing to SAAMI specs. Sizing to match the chamber yields best accuracy AND case life.

why chase the game when the bullet can get em from here?....
Got Balistics?

richbug

I made the mistake once of loading 2000 rounds of 223 that was almost too long for my AR-15 chamber. It worked in the mini-14 and my bolt guns, but was a hair tight in the AR. It functions fine as long as the gun chambers the round itself, but if it is the first round after a bolt lock, or using the charging handle, it sometimes doesn't close and I have to use the forward assist. I will probably get a set of small base dies just for it, as I was already turning the dies to touch the shell holder. Headspace on the AR just closes on a "GO" ga.

.

bpost

Have you made sure you are not over maximum length on the brass. The sizing die might be doing fine but you could be jambing the brass into the throat if the cases are too long.

je2140

Thanks for the input, may think about getting some gauges.
I trimmed to length 1-2 firings ago so I don't think the cases are to long. I probably didn't seat the small base dies down far enough to compensate for the give in the press, to touch shell holder.

JR
The truth is that all good modern rifles are efficient weapons; it is the man behind the gun that makes the difference

Theodore Roosevelt

JustC

The give in the press is not the issue, it is setting it far enough down to resize the expansion ring at the rear of the case. That area ia the major cause of feeding issues in tight chambers.

why chase the game when the bullet can get em from here?....
Got Balistics?

D.S.COLE

Buy a small base sizing die and use it for semi-autos ,lever actions or pumps. That is why they make them. It will cure your problem without all the hi-tech mumbo jumbo and confusion stated so far.
the base is squeezed down a few thouandths in this die and they will seat in chambers easily without the camming power of a bolt action.

<BR>

I.Shute

D.S.Cole-
That's what I was trying to say.
You said it better.