I slugged my two groove '03 barrel. How?

[cropcirclewalker]

Ok, so in preparation to load up a bunch of boolits for my "tactical" shootin', I finally decided to slug my barrel.

It's a fairly good condition Remington 1944 two groover. On my Sportified 1903 Springfield (Springfield 1919 mfgr).

It's only got 2 grooves so on the slug I miked several spots on the groove to groove dimension and got .306 to .3065. If I hold my mouth right sometimes I can get a .307.

The bore came in at .2995 to .300.

This is scary. Lots of .300 and 2 little grooves at .307. What should I be sizing for?

All of these months I have been a member I have been reading about "Beagling" (no offense, Mr. Beagle) and trying to get my .311 moulds to drop a little bigger.

I know, I know, I shoulda slugged it sooner.

I have been sizing my boolits at .311.

I have a .309 sizer too.

What do anybody think? Should I send away for a .308 sizer?

I have been trying to get my 311284, 31141, 311466, 311291 and 311465 to be big enough for my .303s which slug at .3145.

I sense that what I have been helping on the .303 end, I have been hurting on the .308 end.

Thoughts?

[StarMetal]

The throat

Joe

[cropcirclewalker]

Not the little button looking thing which gets stuffed into the cartridge, but the book that helps us noobies to understand.........

Zackly what is the throat?

Ps. and edited to add........It seems like it took more serious walloping with my wooden mallet to get the lead slug started in the breech. Then, as I smacked it down the bore toward the muzzle, it seemed to get easier, wherin in the last couple of inches of the barrel, I just sort of stroked the (3/16" x 36" brazing rod) and the slug came out the end with no mallet.

[Char-Gar]

The throat is that part of the barrel just ahead of the chamber and behind the start of the rifling. Many chambering reamers cut the throat as a part of the chambering process.

The idea is to have the bullet an exact fit to the throat. That way the bullet enters the barrel dead straight, which is a major asset to accuracy.

I can save you some hastle. Just size those bullets .311 and they will fit your Remington throat just fine and you will get good accuracy if everything else is right.

[StarMetal]

You need to slug the barrel breech end and muzzle end separately. It's not good the slug got easier to push as it neared the muzzle. Ideally tighter at the muzzle would be better. But that might not matter too much with a two groove barrel as alot of the bore in lands.

Joe

[Bass Ackward]

Ps. and edited to add........It seems like it took more serious walloping with my wooden mallet to get the lead slug started in the breech. Then, as I smacked it down the bore toward the muzzle, it seemed to get easier, wherin in the last couple of inches of the barrel, I just sort of stroked the (3/16" x 36" brazing rod) and the slug came out the end with no mallet.


CCW,

Did you have any oil in the bore? You could have been forcing that slug and actually leading, thus reducing the size of your slug until it pushed straight through. Or which is most likely, you could have had some copper traces left in the throat area that distorted the feel and measurements.

And there can be no cheating. The sluging process takes three slugs. One slug in the muzzle and push it back out. One slug in the throat area and push it back out. Then find your smallest dimension by pushing one all the way through.

Diameter is a strange animal. But the faster I go or want to go, the smaller the diameter seems to work better. But I never want to be more than .002 over bore for any reason with a bottle necked case. But I use the lands for alignment. If you have to jump, then choke or fill the throat. obviously the larger diameter you use, the sonner you will contact the taper in a throat which helps ignition. Especially with normal rifle powders.

[slughammer]

As Bass mentioned, it is a good idea to make sure the bore is scrubbed and oilied. You can always put an index mark on the slug and then push it through again to see what you "feel".

I'd recommend doing a pound slug of the chamber, chamber neck and throat. These can get you a bunch of valuable information about your rifle.

87726

[Bob S]

At the end of 1942, the tolerances for bore/groove for U.S. .30 cal weapons were relaxed. The new min/max were .2995/.3015 for bore and .3075/.3095 for groove. That applied to both two-groove and four groove rifling. If you got one on the tight side, that's unusual, but it will probably group very nicely with jacketed stuff. I've got several loose "spare" two groove barrels that go .3093 in the grooves. Of course with cast you can adjust for whatever the internal dimensions are. I size to fill the throat.

Resp'y,
Bob S.

[Billwnr]

I shoot a .312 diameter RCBS 180FN bullet in my 2 groove and it shoots real good. Went with a recommended load of 16.5 grains of 2400 and new cases from the same manufacturing lot.

It's the most accurate shooting military rifle I've shot with cast bullets.

[David R]

Another thing to measure is the inside of a fired case neck.

For example my Savage 222 measures .231. It shoots .228 boolits best because they fit the throat.

Measure a few fired cases and see.

David

[chuebner]

My 1943 03A3 has a slightly tapered bore. Dimension about 2" in from throat, .300 bore, .311 groove. Dimension about 2" in from muzzle, .300 bore, .3085 groove. I size the 311284, 311291 and 311299 to .311 and coat with Liquid Alox. This rifle will shoot honest 2" groups at 100yd. on my good days when I lay off the pot of coffee before going to the range. Oh yea, this is with 10-12gr Unique, 9-13gr Red Dot and 14-16gr 2400. :-D