Moving the shoulder forward

[abunaitoo]

The head space on my 3A Enfield had bad head space.
To move the shoulder forward, I made cases out of 30.06 and full sized to fit.
Worked great.
I have a Israeli Mauser, also in .308.
I remember reading someplace about putting tape around the base of the shell, and fire forming it to move the shoulder forward.
I think they were using a rimed case.
Has anyone tried this for a rimless case?????
Would save me lots of work.

[Hickory]

Headspace adjustment is normally done with the reloading die on fired cases by not setting the shoulder back a few thousands or by setting it back a few thousands over SAAMI recommendations while checking it with a headspace gauge.
Excessive headspace can occur in two forms, by having too long a chamber or having too short of a chamber.

[Hickok]

You can also seat a boolit out into the leade/throat so that it engraves into the rifling. This pushes the case back toward the bolt face, and upon firing, moves the shoulder forward. Reduce you load, as this can raise pressures.

You can also expand the case neck, then partial resize. An expander button from a .303 or 7.62 x 39 die would work. Then just partial resize the neck with your .308 Win. die. This creates a step that fits tightly in the chamber neck, and keeps the case against the bolt face.

[William Yanda]

Sounds like the basis for a new wildcat caliber. What will you call it?

[frkelly74]

You can size the neck bigger, like 8mm or .338 and then partially size it back down to the proper size until it will chamber with a slight crush fit. Then load, leaving shoulder as is, and fire form the case and from then on neck size only. It will be custom made for that chamber and probably not fit any other rifle that has a normal chamber.

I have a .338 expander with the stem that fits RCBS dies that brass magnet gave me and would be happy to pass it along to you if you think you could use it. It might take me a while to find it , we just moved and everything is "lost" for now.

I see Hickok has also suggested this. Great minds work alike.

[country gent]

That's how I have always done it I simply expand necks up 1-2 calibers then sive down leaving a ring to hold headspace with and fire form. This allows correct stamped brass to be used, may not be an advantage if you have several rifles and only one needs this modification. By expanding up to 35 cal and sizing down standard brass can be used. ALl you need is the ring on the case neck to hold it and fire forming does the rest.

[swheeler]

As country gent suggests create a false shoulder to set headspace, I use a slight crush fit, fireform and neck size only on future reloadings. If after several loadings you have trouble chambering rounds you may have to FL resize this brass, if so back your dies off to just touch the shoulder pushing it back .001" or so, you will have a long and happy life with brass treated so.

[RU shooter]

Sounds like the basis for a new wildcat caliber. What will you call it?

7.62 XL (extra long )

[Wayne Smith]

The tape is for special cases where the diameter of the cartridge is slightly less than the diameter of the chamber (e.g.30-06 in 7.7 Jap). This centers the brass in the chamber, the case expands ahead of the tape, and you have a case that, on the second firing, without the tape, will be expanded to the web to be centered in the chamber. It has nothing to do with the shoulder.

[coloraydo]

That's how I have always done it I simply expand necks up 1-2 calibers then sive down leaving a ring to hold headspace with and fire form. This allows correct stamped brass to be used, may not be an advantage if you have several rifles and only one needs this modification. By expanding up to 35 cal and sizing down standard brass can be used. ALl you need is the ring on the case neck to hold it and fire forming does the rest.

Sorry for piggybacking and don't want to derail this thread, but would this process work ok for an M1-A? I was given several hundred cases that appear to have been overly f/l sized, pushing the shoulder back excessively. Was wondering if the small ring left after sizing up, then neck sizing back down would hold up to the semi auto forces exerted upon chambering.
Thanks in advance.

[abunaitoo]

Great idea over sizing the neck.
I'll get on it.
Thanks

[Wayne Smith]

Sorry for piggybacking and don't want to derail this thread, but would this process work ok for an M1-A? I was given several hundred cases that appear to have been overly f/l sized, pushing the shoulder back excessively. Was wondering if the small ring left after sizing up, then neck sizing back down would hold up to the semi auto forces exerted upon chambering.
Thanks in advance.

It should work in any rifle. You may have to be a little more exact in an autoloader because of the lesser camming power it has compared to a bolt action.

[country gent]

he other thing to watch is the rings position on the neck shoulder of the case as crush fitting is not as easily / safely accomplished in the semi auto. I might also consider a fresh new extractor spring and extractor to make sure the head stays back.

[Reverend Al]

Up here in Canada we run into this quite regularly since it seems that every 3rd rifle you see is an ex-military Lee Enfield, P-14 Enfield, or Ross rifle chambered in .303 British. Headspace issues crop up regularly with this cartridge and as mentioned above the easy fix is to neck expand the case mouths until they are oversized, slowly adjust your sizer die down until you create a "false shoulder" at proper headspace for your rifle, and then fire-form. If you have more than one rifle in the same calibre you can always mark the "headspaced" brass on the base with a distinctive colour of felt marker.

[abunaitoo]

Only going to be used in the one rifle it's made for.
Also only going to be cast boolets.

[jimb16]

I know one guy who used tight O-rings in the extractor groove to hold the case head/ primer against the firing pin. Seemed to work well for him

[abunaitoo]

Made 40 shells to try this weekend.
I found a flat washer that fit the shell.
Sanded it thinner until it was the correct size.
Now when I resize, I can just use the washer so the shoulder won't get pushed back down.
Will be neck sized only with the Lee Collet die.

[abunaitoo]

Shot them yesterday.
Didn't expect much. Doing it mostly to form the shells.
Accuracy was much better than before.
Shoulder did move noticeably forward.
I'll neck size and work up loads.
Much thanks for the suggestion.

[Moonie]

I've got a mauser with a long chamber, I load a light load and seat boolits to jam into the throat, fireforms them and from then on I neck size. If I need a little more I will adjust the die so that the resized shoulder just fits.

[Hinnerk]

I know one guy who used tight O-rings in the extractor groove to hold the case head/ primer against the firing pin. Seemed to work well for him

I just picked up a pack of 100 size -013 O-rings from Grainger for a coupla bucks with the intention of trying this with my No.1 Mk.III. The bolt closes with effort so I guess that it is good sign that the head is being held tightly against the bolt face.

With regard to that tape thing, I have used 1/4" copper foil tape to center 7.7x58 rounds in my Type 99 Arisaka. As was pointed out, that is a different problem. The tape I used is the sort for stained glass work.