Range report-cast lead 45/70

[snuffy]

Range report-cast lead 45/70

Not to spout off on any supposed skill, just a thread about how different alloys do different things. The first two pics are using a 20 parts pure lead to 1 part tin. Oh the load is as follows. 340 gr. Lee 2 cavity mold RNFP, 27.5 grains of surplus 4759, new starline nickel plated brass, winchester large rifle primer. Rifle is a H&R buffalo classic SS sporting a 3X9 B&L scope. Range was 100 yds, temp was low 70's slight breeze. (beautiful early summer Wisconsin weather!) (finally!).


http://photos.imageevent.com/jptowns/arrow/websize/340%2020-1.jpg

http://photos.imageevent.com/jptowns/arrow/websize/340%2020-1-2.jpg

This next picture is the same load as above, the difference is the lead alloy. These were a mix of some dead soft, nearly pure lead I got from a scrapped machine counter weight. Mixed with linotype metal, 17 lbs. weight metal to 3 pounds of lino. BHN is around 15.

http://photos.imageevent.com/jptowns/arrow/websize/340%2017-1.jpg

The group is over 6 inches, the best of the first two is 2.138 Not bad for an old f**t and an inexpensive single shot rifle!

Oh, the chrono readings are as follows:

Best of 2 5 shot strings with the harder alloy.
AV 1610
hi 1652
lo 1568
ES 83.3
SD 30.6
AD 20.5

Then a 10 shot string for the 20-1 alloy
AV 1573
HI 1605
LO 1561
ES 44.5
SD 13.1
AD 8.5

Why the higher vel. with the harder lead? I dunno. The worse readings,(the first string), were 83.3 ES, and that is the last group pictured.
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[Larry Gibson]

I doubt the loss of accuracy is alloy related. It much more likely velocity related. This is a phenomenon with PB cast bullets. I recently was testing some commercial cast 415 gr bullets in my Siamese Mauser 45-70. Up through 1550 fps I was getting 2 moa accuracy at 100 yards. At 1600 fps groups opened to 6 moa. I rand this test 3 times to confirm that it was not an anomaly. I have also found this phenomenon to be the case with all PB cast bullets regardless of caliber. You can get higher velocity with accuracy going to harder alloys and FBs instead of BBs.

Good shooting with those first groups BTW.

Larry Gibson

[garandsrus]

Larry,

I think 15050 fps is outside the RPM threshold :)

John

[runfiverun]

the pain threshold also.
but the malleability of the lead could easily play a part in accuracy.

[Larry Gibson]

Wow! No wonder it's inaccurate..given the 22" twist of my rifle that's 492,635 RPM! "Smokin"!

Naw it should have been 1550 fps but you guys knew that. I've edited it. Thanks for the update.

Larry Gibson

[montana_charlie]

I doubt the loss of accuracy is alloy related. It much more likely velocity related.
In a way, I agree with Larry. But I'm not referring to pure velocity.
The ES for your 'hard bullet' loads is double that for the others. Inconsisent velocity is worse (to me) than too much or too little velocity.
CM

[John Boy]

Snuffy - WW's will shoot. There's 14 bullets through that ragged hole
http://i222.photobucket.com/albums/dd220/Meadowmucker/Targets/LymanPostell100Yds.jpg

[snuffy]

Thanks for the good comments. I'm real happy with the results with this rifle. It shoots a lot of different loads with good accuracy. Even those dreaded j-word projectiles. But I haven't shot any jacketed for a while.

I'm going to spend a lot of time this summer with the 340 lee and 405 HB lee boolits. I also cast some of the 405's out of the 20-1 alloy, can't wait to try some loads with them, now that shootin weather is here.

[Junior1942]

You put a 3x9 scope on a Buffalo Classic barrel?

[snuffy]

You put a 3x9 scope on a Buffalo Classic barrel?

Yes. I'm 62 with corrected vision to 20-20 and trifocals. Even with the excellent peep sights front and back, I could only shoot well at 50 yards. I felt that I needed at least 100 yds to see how the loads were really doing. So I mounted the scope.

[Naphtali]

Wow! No wonder it's inaccurate..given the 22" twist of my rifle that's 492,635 RPM! "Smokin"!

Naw it should have been 1550 fps but you guys knew that. I've edited it. Thanks for the update.

Larry GibsonAre these references to RPMs related to Greenhill's formula for calculating correct rate of twist with non-jacketed bullets?

[jack19512]

You put a 3x9 scope on a Buffalo Classic barrel?







I did this also. I tried using the stock sights but with my eyes I couldn't work up my loads as easily as I could with a scope. Without the scope I didn't know if my not so good groups were because of my eyes or my reloads.