.50 Great Plains @ 50, 75, 100 & 125 Yards

[Semisane]

I had a nice shooting session with my .50 Great Plains Saturday afternoon.



This gem was purchased last June from a Mom & Pop shop as "new/old stock". The factory inspection sticker in the box was dated April 18, 2000. I've put about 150 rounds out of it so far.

Shooting conditions were pleasant - 68 degrees, high overcast, with the sun peeking out now and then. I took five shots each at 50, 75, 100, and 125 yards - all with 105 grains of GOEX FFFg and Lee mold cast balls in .018 pillow tick patch lubed with Liquid Wrench.

Here are the targets.

50 YARDS



75 YARDS



100 YARDS



125 YARDS



As you can see, I got a few flyers. Also, I switched to a five-inch bull for the 125 yard target so I could see the dang thing.

So, where did those other two shots go on the 125 yard target?

THEY WENT HERE.



I'm fairly certain the flyers were not my fault. I was shooting carefully and they are just too far out of group to be shooter error. I managed to recover all of the patches from those twenty shots and found several that appear to have torn on loading. So I'm going to blame the flyers on that.

 

[yelnif]

Hello Semisane, That is some impressive shooting there. You might check your barrel crown for a slight rifling burr. Some on this forum have suggested using 1000/ 2000 grit wet/dry paper and polishing the crown using your thumb to provide pressure on the w/d paper.
BTW- great looking GPR, I'm partial to dark wood and iron furniture also. Some day I hope to have one.

 

[azmntman]

VERY nice grouping :hatsoff: . Even with the fliers. I'd be dang proud! My look into one of those.

 

[rdrash]

You got me beat. That's very impressive Shooting
:hatsoff:
Trevor

 

[Semisane]

You might check your barrel crown for a slight rifling burr.

Right on yelnif. I'm pretty sure that's the culprit. This afternoon I hit the crown lightly with some 600 grit emery paper.

One thing that puzzles me though. You may have noticed that I adjusted the sight a bit left after the 50 yard target, and the 75 and 100 yard shots were pretty well centered on the bull. So why are the hits so far to the right at 125 yards?

 

[Flint62Smoothie]

RH twist ...

 

[Sean Gadhar]

Did ya weigh the RBs? hate to think you work to fix a gun thing, when it might be an air bubble thing.

 

[Semisane]

Yep Sean, the balls were weighed and sorted in half grain increments. All of those used for this shoot were in the 176.0 to 176.4 grain range.

 

[Semisane]

RH twist ...

Hey Flint, would that come into play only in that last 25 yard increment from 100 to 125? It would seem that if twist were a factor in would be evident throughout the range. Or does it start to occur as the velocity slows?

 

[don hepler]

Nice shooting!!!! No telling what that rifle would do with peep sight. I don't think I could even see a 5" circle at 125 yds. I saw a rifle just like that, last week, at a LGS. Beautiful....rifles.

 

[Semisane]

I do have a Lyman peep sight on it hadden. The picture of the gun was taken before the peep was installed.

No way could I get those groups with open sights. I don't even bother to try beyond 75 yards without a peep.

 

[Mr. S]

Very nice shooting semisane! I haven't shot my GPR past 50 yards yet. I also have a Lyman peep sight on it and am very happy with the accuracy. I use a .535 RB with pre-lubed .015 patches over 80 grains of Goex 3F.

My eyes aren't the best and the peep sight sure does help me. Again, very nice shooting!

Rick

 

[don hepler]

Good shooting anyway.... Yes it's hard to beat a Lyman sight, especially at long range.

 

[Shooey]

Great shooting! Figure out that flyer and you'll be in good shape!

 

[Dphar]

The fliers are a PITA. Did you have ANY wind? At 50 yards just a little puff can move a ball an inch or more. At 125 it can be a pretty significant movement. Several inches to a foot.

I would play around with powder charges if you have not already, 90 gr of FFF often works really well in 50s. Did you wipe between shots?
Petroleum distillate would not be my first choice for patch lube either. Some petroleum compounds can cause problems with the fouling being pressure cooked into something like asphaltic concrete that can be very difficult to remove.
Unless using a water based lube, which I would rather not do, wiping is necessary for best accuracy. UNIFORM wiping and drying with a not too wet "wet" patch and a dry one.
I use a jag that is small enough that it will let the patch ride over most fouling then tighten when the patch is drawn back out.
Finally and perhaps this is the whole problem, I have had very poor result lately with any striped ticking I could find. I had used the stuff for decades but the now imported cloth is too weak. I have switched to denim.
I would also order the information for sale here. http://www.blackpowderrifleaccuracy.com/

Dan

 

[yelnif]

You might check your barrel crown for a slight rifling burr.

Right on yelnif. I'm pretty sure that's the culprit. This afternoon I hit the crown lightly with some 600 grit emery paper.

One thing that puzzles me though. You may have noticed that I adjusted the sight a bit left after the 50 yard target, and the 75 and 100 yard shots were pretty well centered on the bull. So why are the hits so far to the right at 125 yards?

The elimination of the patch tearing burr may also improve the accuracy. Before doing anything else I would suggest that you return to the range. Try to pick a windless day and wipe between shots, preferably with a water base lube as this will help to lessen fouling problems.
For at the range I often take old arrows, with a 20" strip of florescent streamer attached to the top, and stick them in the ground at 25 yard increments out to my farthest target. It helps to ''see'' the wind if you get my drift.

 

[Semisane]

Dan, not only are fliers a PITA - they are the work of the evil twins Dangaflyer & Screwdagroup. (See Chart Below.)

Good thought on wind as a factor. I hadn't considered that because our hunting club rifle range is bordered on both sides by tall pines and wind is seldom an issue. But thinking back, the targets did flap on the backboard a few times during that shoot.

Regarding the powder charge, when I first got the gun I shot groups at 50 yards with FFg and FFFg in five grain increments from 80 to 120 grains, and 105 grains of FFFg was a real sweet spot.

I've used nothing but Liquid Wrench as a patch lube for the last few years and will use nothing else in all of my ball guns from .32 to .58 caliber. It has proved itself (to me anyway) as a superb patch lube. I alway wipe between shots with one down and up stroke of 91% Isopropryl alcohol. No nasty fouling - no "tar" - no unusual cleaning issues.

The patching I'm using is from the same lot I've been using in two Renegades mounted with.54 and .58 Green Mountain barrels with no tearing or blow-by issues. So I don't think that's the issue. However, I do have some .020 denim that I may try. Regardless, I do believe the crown of the Great Plains just needs a bit of polish.

 

[Mickc01]

Very impressed. A few of my rifle-guns may be able to shoot that well but I sure can't. :hatsoff: :hatsoff:

 

[cowpoke1955]

Great shooying Semi :hatsoff: From a nench, I've squeezed out a few 3/4" groups at 100 yards with my .54 GPR flinter, 530 ball, pillow ticking patch lubed with Ballistol ans 90 grains of FFg Goex. These rifles will do it :thumbsup:

 

[roundball]

Good testing there...and as you probably know, sometime a little wool/felt OP wad can tweak things up some more too.
PS: I'm guessing the reference to 195grns 3F on the last target is typo :wink: