Neck Sizing

Ammunition, reloading, shooting, etc
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Olpeddler
Posts: 65
Joined: Sat Nov 16, 2019 8:30 pm

Neck Sizing

Post by Olpeddler »

I finally have my 1899 Carbine shooting pretty well using Hornady Interlock bullets 1.e., 165 gr BTSP's (39 grs AA 2520), 180 gr RN's (36 grs AA 2520), and 220 gr RN's (33 grs R/15). At 75 yards I'm generally getting 3" - 4" groups from a bench rest. Recall, when I first acquired my Krag in 2019, I was shooting 2' high at 50 yds. 3 factors have contributed to this better accuracy: (1) My gunsmith installed a shorter front post sight which many of you recommended to me 2 years ago, (2) my conversion to AA 2520 powder for the 165 and 180 gr bullets, and (3) I have learned how to adjust the model 1901 rear sight.

My long-term goal is to shoot 2" groups at 75 yds. with all 3 bullet weights. I am thinking neck sizing my brass will somewhat improve accuracy. About 10 years ago I began neck sizing for each of my 4 bolt action .30-06 rifles using a Redding neck sizing die. Versus f/l sizing, neck sized rounds in these rifle generally deliver 25% tighter groups than f/l sized rounds at 100, 150, and 200 yds. I use AA 2520 power and 165 gr Hornady bullets in reloading for each of these rifle.

I would appreciate any input from forum members regarding your experiences using neck sized .30-40 Krag brass, and the sizing dies you use. Thanks in advance for anything you can share with me.

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Parashooter
Posts: 706
Joined: Thu Feb 04, 2010 5:14 am
Location: Kragmudgeon House, CT

Re: Neck Sizing

Post by Parashooter »

Don't expect much improvement with neck-sizing for a Krag. The long, wide throat in most of them means bullet design is more critical than initial alignment.

If you have a decent die collection, you might avoid the expense of a .30/40 neck die. A properly-dimensioned neck sizer is cut large enough everywhere but the neck to avoid touching body and shoulder of the fired case for which it is designed. Concentricity is dependent on alignment of die and shellholder plus uniformity of case neck wall thickness and hardness. Consequently, it shouldn't make any difference if we use a die designed for a larger-bodied case as long as neck diameter is appropriate and base-to-neck length not too great to allow adjustment to size neck near depth to which bullet will be seated. I often use a 7.65x53 Mauser FL die to neck size .303 British - and .308 Win. FL sizer for .30/40 Krag with .308" bullets. When loading .311"+ cast bullets for the Krag, the 7.65x53 die does the job nicely.)

madsenshooter
Posts: 1176
Joined: Thu Sep 10, 2009 5:00 am
Location: Upper Appalachia aka SE Ohio

Re: Neck Sizing

Post by madsenshooter »

I use a 7.5x55 Swiss Lee Collet Die with a washer between it and shellholder to neck size 30-40 mostly. Since one doesn't have to squeeze the neck all the way down to to the mandrel I can adjust the die to the ID I want. The die doesn't size the whole neck down to the shoulder, about 2/3. Whether or not that additional support helps accuracy any, I can't say, haven't shot enough of them sized that way.

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