Load testing

[Chaz]

Windcutter,

Keeping in mind that I am a rookie to basically every degree of this type shooting. I have a question? Imagine that. I was load testing a 40-70SS and got a fairly decent group at 100 yds ( all thats available) 6 shots out of 10 in a 1 1/2" , 3 others within a half inch of that. So the load appears to be a good starting point. Used the same load a week later same weather conditions, a slight crossing wind. Vertically the group was along the same size, horizontally it was approx. 3" long for one group and 4" for the other group seperated by about 2" between the two groups. Wasn't trying to shoot two groups, however the second five shots dropped 2". I was using 58.5 grns. of Swiss FFg, Rem. 91/2 primer, .030 veg. wad, .010 compression, .405 Hornady brass cut down, and a 400 grain RCBS bullet cast in 2o to 1. I think thats everything. In an earlier post about this mold the general feeling is this bullet may be to long for twist rate(1 in 18). So If I were to take this mold and enlarge the grease grooves to carry more grease would this weight reduction help stabilize the bullet? Examining the bullet holes at a hundred yards there is no evidence of keyholing. Would this show up at this range or would you need to shoot at 300 or so to find this out? I do not know the actual cast weight of the bullets, but the previuos replies I recieved feel that I should use a 375 grn bullet. Chaz

[Don in PA]

Chaz
It's not the weight of the bullet that causes unstaliztion  it's the length of the bullet. Opening the grooves will not change the length.
 I don't shoot a 40-70 but one of the guys I shoot with does and I notice his bullets are way out of the case (three grooves showing) he says he need this COAL to get the bullets to touch the rifling for his best accuracy.
Usually horz. movement is caused by pilot error or the wind. The two group problem may be a machinal problem loose sight or something.
Was the barrel located on the rest at the same spot through out the shoot if not this can also cause two groups.
 
Don

[Lead pot]

Chaz.I been following a nother forum>the subject is "Moist shooting black powder".

I was interested in that subject.So I found some swiss and baught several cans of 1- 1/2 and 2FI just about always burn Goex.A lot of discussion was on the accuracy of the Swiss geing better than Goex.
I ran a test several weeks ago when the weather was still warm ,I think in the low 40's.I ran a string of swiss and goex through my .40-70 Shiloh and .45-70 Browning BPCR.I didnt know were to start the Swiss for compression so I started with none except .060 fiber and awad cut from a plastic coffee can lid that I normally use.Well boath rifles with eather powders performed the same,3"at 200 yds.The swiss had more cut than the Goex.
Today I went back out and the temp was 14 or 15 degrees the wind was about 15mph from behind so a nofactor.I just shot the .40-70 with 15 rounds each and again boath shot the same, so I cant say one is better than the other.
As far as one burning more moist than the other I could not tell any difference.
To get at your groops on your shots with the horozontal stringing,I blame that when I do it on fat fingering or lost my stock weld.
When I get vertical strings like I did today for 5 shots is from blow tubing to much.I normly blow 4-5 times on warm days.But today it was a little cool and the moisture condenses a little more so one blow was enough.

I never found my .40-70 keyhole.I have shot 300 grainers,they fly straight but my rifle dont like the short bullet with a 16 twist.I use a 420 gr.bullet with a 3 lube groove bullet.
This turned out to be strung out longer than  I wanted to be but I would like to hear about some of the test's you ran on your .40-70.Some people say the .40-70SS dont shoot,you could'nt prove that by me.Mine shoots.

Kurt.

[Chaz]

Leadpot,

I'm still in the early stages of testing, best group I got was the one I talked about in my other post. Shot last weekend with Don, who also post here. A lot of ground fog, setup new sight, unable to get any groups think it was more that I couldn't see than any thing else. In my earlier shooting I found that 3 breaths were good for 4 or 5 shots then I would need 4 or 5 for the last 5 to keep them together.Going to try a Lyman bullet next it''s a little lighter and shorter 410660. Chaz