Home Forums Reloading Big Game Rifles False shoulders

I've never used one, but am considering it for forming AI brass. How many think a false shoulder is better than just seating the bullet into the lands, or how many do neither?

Is there a rule of thumb for the diameter of the false shoulder vs. the bore diameter, e.g., for a 6.5 mm. bore, would a .277, .284. or larger shoulder be needed?

I've used .35 for .30 false shoulders

I always go two bore sizes up at least.

I do think the false shoulder does a better job of centering the cartridge in the chamber.

I don't do it for AI's, they should already have a 'crush' fit from a slightly negative headspace. If not lands/false shoulder will get you there.

I use .280 Rem dies for my .25-06AI... Monashee

So...


If I were a False shoulder... what would I be?



T

I have some virgin brass I'll be using, I was assuming there'll be positive headspace for the new stuff at least. Don't have the barrel yet so I can't check. I'm gonna have to neck it up to 264 from 257 anyway, which is one of the reasons I was thinking of the false shoulder.

If done right it should have a NEGATIVE headspace. Typically they are cut about .004" under for that crush fit.

Got it. Never had an AI chambered rifle before, so it's all new to me.

That should make things easier.

I just did it for my large chamber Savage 99 250 Savage. I had some once fired 22-250 brass fired in a tight chamber.

Bumped it up to 7mm then down to .25 leaving a very small shoulder that closes snug. Wanting longer case life than 4 firings moderate load.

I use false shoulders also, something else I do is remove the firing pin and spring from my rifle bolts when setting up the sizing die. I have a better feel for the slight crush fit when closing the bolt without the tension of the firing pin spring on it.
Hope that helps also,
BD

For my 7-08AI, I neck down .308 brass until it just chambers and neck turn just enough to eliminate any high spots.

A properly cut AI chamber is built to shoot factory ammo. No false shoulder should be required

I hate to agree with Scott, but since this has nothing to do with women, I guess it is alright.

I have used a false shoulder on a couple of rigs. One was a 22-250 which had excessive headspace. For several years, instead of rechambering the barrel, I necked my brass to 243 and then back to 224 and set the die for a crush fir in the chamber.

Essentially I converted the rifle into a wildcat.

The other case is with the same barrel after I had it reamed to 22-243AI. I run the 243 brass into the sizer just far enough to ensure a crush fir for the first fire forming load.


With my rifles, 243 to 224 was plenty of shoulder to maintain headspace.

In cases where secure headspacing is needed, such as fire forming a cartridge with a shorter neck than the parent case, a false shoulder is preferable to seating into the lands.

Seated bullets have been known to move in the case and change cartridge length. Bullets seated into the lands have been known to stick there when one removes a cartridge from the chamber.

Thanks all for the advice. 'Dog, I hadn't heard this one but I'm gonna try it.

If the smith is worth a hoot you won't need to do all that, you WILL feel the crush fit.

Well, that's the advice I was talking about, now I don't have to worry with it. Pac-nor's doing the re-barrel. 6.5-06.

What you going to make brass from?

I'd make it from 25/06, that's for certain.

What's wrong with necking down 270, other than needing to trim for length afterward?

The least amount of change one can do the better off they are. Hell, I can about seat a 6.5 bullet in a fired 25/06 case.

Course you did mention 'trim for length afterward' and the fact that you have to ask what is wrong about that gives me pause....