miserable accuracy 7x57

good morning all...and happy 4th to you !
started my day by reading the The Declaration of Independence....then went to the range with my 7x57's
Rolling Block, Ruger #1, and 1893 Mauser
shooting 165 gr RN Cast....sized 0.285 and 0.286 with 40 grains of IMR4350
100 yds shooting from kneeling with sticks results not so good (but had fun)
1895 (scoped sight)....all over the place ! got worse as the barrel heated up
Ruger #1(scoped sight)....most consistent but gradually opened up as the barrel heated
Rem RB......(iron sights)...again not consistent and again the point of impact got worse as the barrel heated.

but it was fun burning powder....40 rds worth...just was not a very accurate load

have a great 4th
ATR

Only a speculation mind you, but...The '93 may very well be needing a .289" or better projectile. Leading???

The Rolling block could be large as well.

Your cast bullets are close to the correct size for the Ruger but are undersized for the other 2 rifles. They will probably need .288 - .290 sized cast bullets. Also your load of 40 gr 4350 is pushing the cast bullets way too fast for the twist of the barrels. You may want to drop to 30 gr, use a Dacron filler and work up to 35 gr. Better would be to switch to a medium burning powders such as H4895. Start at 24 gr and work up to 30 gr using a Dacron filler also.

Larry Gibson

thanks guys...I have shot accurately with the .285-6 in both the M93 and RB...but using 16gr of 2400...so yes I think the velocity was too high..just thought I would try it as an "experiment"....I will stick with the 16/2400
thanks for the thoughts
atr

My M 93 had a groove diameter of .293"; I finally rebarreled the action. Guess the original barrel might of worked with paper patched boolits.

Opps...mine is a 1895...I miss-typed. and the barrel slugged at .286

Quote:

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Originally Posted by atr

Opps...mine is a 1895...I miss-typed. and the barrel slugged at .286

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My 7x57 is a Chilean M95 and also has a .286 groove diameter. Shoots cast extremely well with .287 sized old original RCBS Loverin style 28-168-FN.

Attachment 199170

Larry Gibson

thanks Larry
That is a nice looking mold you are showing.
my 160+ drops a t 0.287..so next time I will leave it un-sized and I will slow it down.

I have a 150 gr Loverin that shoots extremely well in my Ruger....so I will stick with that.

the 40 gr of 4350 was just a fun experiment....back to basics with 16 gr of 2400

FYI; actually .286/.287 is the correct size for European and S. American made 7x57 barrels. The .284 was the British 7mm size that we Americans also adopted as "correct" for 7mm.

Larry Gibson

I agree the bullet is too small. As the barrel expands from heat, the problem grows worse.

Just a matter of strange things, I had a 7X57 that wouldn't shoot worth beans from the bench, but was extremely accurate offhand. Never had a rifle like that before.