7x57 #1 RSI Load Success

[Boatbuilder]

Cooking up loads for my mule deer tag, I found that 47.5 grains of Reloader 19 with 160 grain Nosler Partitions (listed as max by Nosler manual) will shoot 3/4" groups all morning in my RSI, even after the barrel heats up. Some other recipes will string vertically a bit, but not like my 1As do after they get warm. 175 grain factory soft points seem consistent as well, so just loaded up some 175 Partitions to try as backup for the 35 Whelen 1A for elk season. I am pleasantly surprised at how well this RSI shoots the heavier bullets. I never got it to group well with 140 grain factory loads or anything I loaded at that weight. Tried the heavier stuff for fun and wow, what a difference. I don't own a chronograph so I don't know what velocity I'm getting, but who cares - it's putting quality bullets on target reliably. Heading into deer and elk season with great confidence in this rifle. The trigger job I paid for a few years ago now seems to be worth the money.

The 35 Whelen 1A needs a bit more experimentation, but so far 58 grains of Reloader 15 behind 225 grain Partitions is working pretty well with a cold barrel. Rubber thingy trick and forearm screw tension adjustments change performance dramatically in this rifle. I scored an early season rifle cow tag, so need to get this one nailed down soon. The only problem is that RL15 is essentially unobtainable in CO Springs for months now or online. IMR 4064 is giving decent results, but now I need to go through the forearm screw tension sequence again. All good fun, when work permits.

 

[Silent Sam]

How long is the throat on 7x57?

 

[Clark]

I've got the same rifle and have been pondering reloading for it, in particular I'd like to try some Barnes bullets.

I think Silent Sam's question is a good one and one that would be interesting to test with the copper bullets. Since they are less dense they are larger for any given diameter and weight a 140 grain 7 mm bullet might be the same size as the lead 175 grainers. If the throat is long and it's just a matter of shooting longer bullets than the 140 grain copper should work well too.

Clark

 

[Boatbuilder]

How long is the throat on 7x57?

I have never tried to measure it. I'm fairly new to reloading and so far seat to just under the max OA in the manual. I'm familiar with how to do it in a bolt gun, but not sure how in a falling block. If you have a suggestion, I'm game to try.

 

[Silent Sam]

Do it the same way as a bolt gun. Crimp a fired case so it will hold a bullet but still allow it to be moved. "Paint" the bullet w/ a marker, start it in the neck and chamber it. If you reach the lands it will mark the bullet and the neck will mark the bullet as the bullet is forced into the case when it contacts the lands. Do it several times to get a repeatable measurement of OAL. The OAL listed in the manual is the "spec" but it really amounts to a suggestion as throat dimensions vary widely and will eventually lengthen if the gun is shot enough. 7x57 #1s are throated pretty long in my experience which is a probable factor that many of them shoot heavier (longer) bullets better than lighter.

 

[chuck]

On your 35 whelen try 250 gr bullets, I couldnt get mine to group with light bullets but with 250 grainers I get 5 in a ragged hole at 100 yards, my rifle is a ruger 77 tang safety