Black Powder group movement

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  • Last Post 19 August 2017
tlkeizer posted this 10 August 2017

Greetings,

Had an interesting time at the range today.  First, I re-sighted the 25-06 from cast to jacketed bullets for hunting season.  First shot, scope adjustment, 2nd shot scope adjustment, 3rd and 4th shots hit the half-inch target.  Very satisfying.

Second, shot to verify the 45-70 trapdoor loads for hunting.  WOW.  The first 2 shots were off the box the paper was on,, moved the box to 50 yards, hit the box an inch below the top with the box set long side vertical while siting just below the middle of the box.  Glad I was not shooting at the grizzly bear the neighbor shot on Sunday (seriously).  So, at 50 yards, I was 11 inches high, but only 3 inches right while expecting an inch high and 2 inches right.  The big question in my mind was "What the ------".

Some thoughts:  The load was nominally the same I have been using the past few years with the following slight (?) changes.  A) Lead was mostly pure lead, not wheel weights or the like.  Same mold, bullet weight withing 3 grains of other castings (416 grain mold).  B)  Cartridge cases were new Remington cases, first time used, sized and checked for length.  All the same length and measured for length.  C)  New can of powder, GOEX FFG.  I did not check the batch number against the prior cans, but never had such a difference before when changing cans of powder.  D) New to me box of CCI 250 primers.  Old box of primers, but new set used along with new powder and new cases.

Barrel was cleaned and swabbed as I have been doing before, damp patch after the shot and 2 dry patches, then next shot.  First shot from clean barrel out of the gun safe imprinted basically the same place as the 2nd shot I think and neither showed up on the box with the target, but that is conjecture.

The old cases I have been using for a few years, a mixture of Remington and WW cases, have not had the loads fired as I did not bring them to the range.  I have a lighter bullet in them than my "420" and "500" grain hunting bullets.

Sooooo, anyone else experience the same thing when going to a new set of cases?  Does having new brass give that much of a better seal to raise the bullet strike nearly a foot?  Having three slight changes does make limiting the cause a bit of a quandary.

TK

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onondaga posted this 10 August 2017

Tk,

That's a big difference in impact. Was your "mostly pure lead" different from the alloy you used last? That could be responsible for impact difference more than the powder, primers and brass. Alloy directly is effected by load pressure more than the other components of the load if the other components were close , but 1' is a lot.

Do you have any of the old load that grouped where the sights were set? Can you duplicate those loads?

You might be able to verify a reason by comparison side by side.

I use certified alloy for all my hunting bullets to keep consistency and avoid changing that alloy component of my loads. That does help a lot, but, if you can't do that then consider at least using the same batch of alloy for as large of a batch of bullets as you can to avoid changing alloys and effecting POI dramatically.

The recoil of a 45-70 is a big part of what sets  the sight setting where it needs to be and heavy big caliber bullet impacts are dramatically changed when recoil is changed. A different alloy, even with a like charge can hit way different on paper.

 

Gary

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R. Dupraz posted this 10 August 2017

Terry:

My guess is that , with every thing else being the same, that "new" can of Goex is of a different lot than what you had before. This is not unusual when changing lots of real black because it is measured by volume and not weight. There can be a significant difference. For anyone who is familiar with real black powder, this is not surprising. 

Back when I was shooting the BPCR, I was buying Goex by the case. And whenever I got a new lot, I would have to develop a new load and re zero  my 45x2.4 Sharps. Most times the variation wasn't that much because I was using a volume measure. and only used a weight to reference a particular lot.

And Iv'e also noticed a variation in accuracy when loading new cases the first time, both with black and smokeless.  

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tlkeizer posted this 18 August 2017

Greetings,

Well, got back to the range today, interesting.  I wanted to compare some new loads with old loads and mixed loads.  So, I had some of the new loads, made some with old cases and new powder, some with old cases and old powder, and some old cases that were loaded a while back.  I also brought along lots of bore patches both damp with solvent and dry; some of my best groups in the past have been to run a damp patch after each shot then one or two dry patches before loading and firing again.

I shot some new loads, with a cleaned barrel between every shot, and at fifty yards covered only about 3/4 of a sheet of paper.  The safest place to be was behind the bull's-eye.  Then I shot some old cases new powder, and the bullets hit about where they had the past couple years; cleaning between each shot.  Then I shot some old cases old powder, and had an ever so slightly better group about and inch below the previous group., cleaning between each shot.  Then I shot the old cases, old powder, loaded a while back, and that was my best group, about an inch below the prior group. cleaning between each shot.  I then decided to unload some new cases onto another target to get the cases so I could reload them after firing once.  I shot 5 shots each of the 420 and 520 grain bullets in new cases without cleaning the barrel (my shoulder was done for the day so I left half the new loads for another day), and when I got down to retrieve the target all 10 shots were in a really nice group where my last set of old cases old powder loaded a while back shots hit.  If I would have had hits like that to begin with I would be out hunting rather than target shooting.  My interim conclusion is that the rifle does not like to shoot these out of a clean barrel.  When I get everything in a 3 inch group without cleaning the bore, and get everything in a 10 inch circle with clean bore every shot, I think I will fire a couple rounds at the range on the way out to the woods.  I found it intriguing that the new case loads gave the greatest spread using a clean barrel.  All the cast bullets comparing loads except the last old group were from the same batch and lubed the same time.

TK

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onondaga posted this 18 August 2017

Terry,

I'd say you got good useful answers by your range time. I'm jealous and haven't been shooting my thumper.

Gary

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Ken Campbell Iowa posted this 18 August 2017

tk ...

wow, i need to learn a lot more about black powder before i try deer hunting with black in my 45-70.

because the first shot counts ....

i see you use the recommended ffg ... what happens if i used ffffg in my ruger 3 with 405 gr castings in a cartridge load  ??

is that equivalent to changing from 4831 to unique in a smokeless load ??  or would it give more consistent ignition ... and hopefully predictable impact for that first shot ??

Black Powder Matters ??

ken

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tlkeizer posted this 18 August 2017

Greetings

Onandaga, thank you for your comment, hope you get out soon.  One thing I will be doing later is load the new once fired cases and see where they imprint on the first shot and out of clean barrels.

Ken, since I have original 45-70 trapdoors, I stick to FFG.  I think your example of 4831 to Unique is a good comparison; I think at the least your shoulder would notice the difference between FFG and FFFFG. Case volume filled might vary too, you don't want to have a large air space; of course with 70 grains I think either powder would be compressed.  BUT, I will stick to FFG and admit to using FFFG a few times when that was all I had but much prefer FFG.  For ignition I use CCI 250, large rifle magnum primers, Winchester LRM primers also when I had some before I was given  a box CCIs.  I have never had a problem with consistent ignition (yet).  If fact, the only time I had ignition problems with black powder was when I built my first muzzle loader, and all that was available to me was Pyrodex  when it first came out.  At -10 or colder it did not like to ignite, but Pyrodex has improved I believe, but since I can get BP I use strictly that.  Going back to first shots accuracy, see what your rifle likes, this is my first experience with accuracy problems on the clean barrel first shot.

Another thought is this batch of bullets was cast with nearly pure lead from lead centered rope (a minor inconvenience getting the lead out) as I wanted to cast with it for comparison to lead with additives (like tin and antimony) and they may be a thousandth or two smaller than the old bullets so the residue in the barrel without cleaning makes a tighter fit.  When I measured them, they were the same at the old 420 bullets, the old 405 bullets are 003 larger than all the 420 bullets (no new castings, just old castings).  So, maybe when I go out hunting next I will take a couple 405 loads to use first, I don't think the difference between 405 grain bullets and 420 grain bullets will be very great at the receiving end.  As a bye, the 500 grain loads are all .002 smaller than the 420, three different molds, three different diameters; discussion for another day.

Have a good day all.

TK

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Ken Campbell Iowa posted this 18 August 2017

thanks tk, now i know about 20 times more about shooting black powder than i did yesterday.

btw, the reason i have ffffg is because when i oopsie-stick a low velocity casted in my barrel .... i use about a pinch of 4fg to gently "" bloop "" it out the barrel ...   key word is * pinch * ...

ken

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tlkeizer posted this 19 August 2017

Greetings,

One other thought that came to me last night is that I normally shoot in colder weather; barrel constriction for tighter fit?"

TK

PS Ken:  I once found a set of small measuring spoons that we gave to a chef friend of ours, the measurements were: a pinch, a dash, a gooch, and a couple other measurements.  Key words are important.

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