Correct .308 sizing die

[Worn_Holster]

I am in the MiHec 308 Hunting Boolit GB. I plan to use the boolits for my Garand which has a new Criterion .308 barrel, and my 1912 Chilean Mauser which has a 1903 A3 2-groove barrel that the Chileans installed in 1961. My questions is will I likely have to purchase different cast boolit sizing dies for the two different rifles?

[Scharfschuetze]

Well...

Slug the bore on both. Compare the difference and then test bullets sized for the larger of the two in both rifles. You might get lucky and then only need to size in one diameter. I have a few 30 cal military rifles and I've sized as large as .310 for them with good success in bores that meet the .300/.308 diameter goal of the barrel makers and in bores that run more like .302/.310.

While it's probably apples and oranges, my best shooting 2 grove Springfield barrel slugged out at .302/.309. For a comparison, let us know what yours is.

[1Shirt]

I would suggest you start by trying .310.
1Shirt!

[ukrifleman]

Definately slug the bore(s) before anything else.
ukrifleman.

[Larry Gibson]

I you are talking about "sizing dies" for the bullets a .311 would be my 1st and probably only choice. If you are talking "sizing dies" to reload the cartridges with I suggest the RCBS X-dies (regular, the SB and "AR dies are not needed).

Larry Gibson

[Smoke4320]

I am real new to the cast boolit world .. but I took Larry's advice on 311 boolit sizing for 308 rifles..
2 rifles 1 FN PBR 308 and 1 300 Blackout .. FN is shooting 5/8" groups with cast 230's subsonic and 155's 3/4" 1800 FPS .. Blackout is coming along nicely just need more time for development .. PC'ing boolits No gas checks and sizing to 311 I get ZERO leading

[Nickle]

I you are talking about "sizing dies" for the bullets a .311 would be my 1st and probably only choice. If you are talking "sizing dies" to reload the cartridges with I suggest the RCBS X-dies (regular, the SB and "AR dies are not needed).

Larry Gibson

Seeing those both of those barrels are real likely to be within the normal tolerances of a .308" barrel, I agree with Larry. .311" sizing ought to be about perfect.

Now, you only need an SB (small base) sizer die if your chamber has a small base. So, try the X dies first, then get an SB sizer ONLY if you need it. They aren't a good purchase purposes, and don't use one unless you really need to. There's a myth out there that you need to run brass previously fired in a machine gun through an SB die to shrink it down enough. That one is about as false as it gets. The regular sizers size the brass at the base enough to fit a rifle chamber, unless the chamber has an unusually tight base. That isn't all that frequent. I've cut chambers using a match reamer that I used Norma 7.7 Jap brass reformed to 308 after. The brass was better, and a closer fit. I wouldn't recommend that in anything other than a match gun, because it's closer than the tolerances are. And, a 308 Winchester chamber base is really generous.

[1500FPS]

You only slug the bore/groove to insure it's not larger then the throat because it's not going to ever shoot then. You shoot the largest bullet that will let the cartridge chamber within reason. I'm talking about the neck of cartridge fitting. Now if you have a bullet that drops in the area of say .311 and up sizing to .309 is too much sizing down a bullet. The less you have to size a bullet the better. So slug your throats on those rifles and see what you have. A person throwing out a bullet sizing size may not necessarily work for you although it does for him.

[WineMan]

Start with a fired case from each. What is the neck OD? Measure the wall thickness and X2. Subtract this from the fired case OD. Take off 0.001 for safety. For example a fired case is 0.340" and has 0.014" thick walls (0.028") you get 0.340-0.028-0.001 = 0.312". Close enough for government work.

I have a M1903A3 with a new 1944 two groove barrel that loves 0.314 sized cast. My M1917 can't shoot cast anything to save its life. Go figure.

Cast is 80% trial and error, 10% luck and 10% Black Magic. Kind of like the Three Bears: Not too hot, not too cold, or just right. The fun is in the chase.

Dave

[Worn_Holster]

What is the best method to slug a rifle barrel?

[Artful]

Soft lead pushed thru the bore. - if you already had a mold you can use soft lead cast boolit - if you don't cast yet you can get buckshot or a muzzle loading ball from the store and push thru - say you have a .357 you want to slug - and you have .375 round balls - you can roll them on a flat surface like your work bench or the floor with a flat board to make a cylinder about .360 in diameter then push them thru your bore to measure.

for your 308 barrel I'd take a #0 buckshot cartridge and cut it open - the shot is going to be about .320 - I'd roll it to be about .313 and then use it to slug with by cleanning and oiling your barrel then from the chamber end pushing the buckshot thru with my one piece steel cleaning rod.

Buckshot #4 is about .24 #1 is about .300 #0 is about .32 and #00 is about .33 -

to measure the throat you can can take one that is larger than a fired case neck and tap it in and out to get an idea of the diameter. - to measure the throat length you can push a boolit into the leade and then carefully put you cleaning rod in from the muzzle and mark where the barrel ends - (I wrap tape around the rod) - then take the boolit out and close the bolt and put the rod back in and mark again the the difference between the two marks is the longest you can seat the boolit out (may not fit in the magazine) of the case for OAL

[Worn_Holster]

It is difficult to push from the chamber end of a Garand.

[Larry Gibson]

It is difficult to push from the chamber end of a Garand.

Can't do it from the chamber end of a M1. Suggest you just go with .311 and not worry about it.

Larry Gibson

[1500FPS]

Do a pound cast to get a very accurate measurement of the throat and also some of the breech end bore/rifling. You will also get a measurement for the neck diameter portion of the chamber.

If you are not going to do any of this just try some sample test loads with bullets sized at .311, .312, and .312. That is if your bullet drops fat enough. If you use anything smaller remember the throat on a Garand is in the vicinity of .312 and that's not counting wear/erosion. A smaller diameter bullet then that is not going to be guided straight and will enter the bore crooked. If you have a tighter throat then that you are lucky.

[Worn_Holster]

I have a new Criterion barrel in .308 installed on my Garand. What is a pound cast and how do you do it?

[uscra112]

I may elicit screams of horror from some, but I slug the breech end of rifles like the Garand by loading about 1 grain of Red Dot behind the largest boolit that will chamber, point muzzle vertical, and fire. That will always lodge the boolit in the bore. Drive it back out with a rod from the muzzle. More or less Red Dot will get the boolit to stop almost anywhere you want.

[Artful]

It is difficult to push from the chamber end of a Garand.

:oops:
Too early in the morning for me gents - my appologies

[1500FPS]

I have a new Criterion barrel in .308 installed on my Garand. What is a pound cast and how do you do it?

First clean your barrel and chamber. Next take a sized case and either fill it to slightly below the neck base with any alloy, or (what I prefer) find a steel or brass rod that will just slip through the neck and be long enough to be at the neck base. Next you need a pure lead slug that is about bore size, not groove size, and long enough for what you want to measure. That is if you want to get some of the beginning of the breech rifling make it that long. Next oil that pure lead measuring slug and place it in the neck of the prepared case. Chamber it. Get a steel or brass rod that is the largest that will fit into the bore from the muzzle. Make sure it has a flat end on the end that will be against the bullet. Place it in the barrel, and I put a marker pen mark on the rod right at the muzzle crown so I can see how much I compress the slug, and they give it a few hard taps with a two to 4 pound hammer. This is where experience of doing this comes in and you can tell when you have compressed the slug. Now carefully extract the case. You may have to use the rod to help push it out. If down right the slug will have stayed in the case and you should have a duplicate of your throat , forcing cone, and however far you made the slug to enter the bore. You should also have expanded the case neck and also have a little bit of the slug filling the very end of the neck area of the chamber. Measure carefully as pure lead is pretty soft.

The smoother that lead slug is and of the largest diameter that will fit the case neck and chamber the better. Some use a pure lead cast bullet, but I don't like that as they have grooves that impact out all the way and may be at a critical area you wish to measure.

It's easier to see it done then reading the instructions which make it sound very difficult which it is not. The other way is to pour Cerosafe into the chamber, but I believe it to be more difficult.

[MtGun44]

Try .311, you will probably be fine without any fiddling.

Bill