GPR Accuracy

[Louisk]

I'm working on sighting in my .54 Lyman Great Plains rifle. I've put over 300 rounds through it now so it should be broken in. It may be my imagination but it almost seems like it was shooting smaller groups when I first got it than it is now. I'm still not sure if it's the sights and my old eyes or something else. It doesn't take a huge amount of force to ram the ball home so I'm wondering if I need a thicker patch or to go from the .530 ball to the .535.

I'm considering removing the buckhorn sight it came with and installing the included primitive sight. Any experiences with that? I'm also thinking about the not so primitive Lyman peep sight although that looks a little more modern than I really like. Thanks!

 

[pab1]

All of mine are .54 cal and very accurate. I don't like the primitive sights that come with them though. The front sight is way too wide to take advantage of the guns potential accuracy IMO. The notch in the rear sight is cut too wide and deep also. I replaced the front and rear sights on all of my GPRs with semi-buckhorn rear and narrower front sight blades from TOTW.

What thickness of patch are you using? All my GPRs and my Plains Pistol have been very accurate with a .530 ball and .018 pillow ticking patch. I use both Bumblin' Bear Grease and Trappers Pure Mink Oil. Both have worked well.

 

[BrownBear]

It doesn't take a huge amount of force to ram the ball home so I'm wondering if I need a thicker patch or to go from the .530 ball to the .535.

That's almost a perfect echo of my experience with every GPR I've owned, both 50 and 54 caliber. At around 300 yards the bore has slickered up enough that seating starts getting pretty easy, and accuracy starts dropping.

You don't mention which patch you're using, but I started out with .530 balls and .015 patches on my latest GPR. At around 300 shots I tried .535's with .015's, and though it helped, I didn't like so much seating effort. Dropping back to .530 and up to .018 fixed all that, with a little easier seating effort and quite a jump in accuracy.

At around shot #2,000 it was getting loosey goosey again, so I moved up to .535's with .015. Just fine, but for some reason I couldn't get my brain around .535, so went to a .022 patch with the .530's and found happiness. It's probably more accurate now than it's ever been.

Dunno how many shots I've actually got through it now. Lots. And I've not found any more reasons to dingle around with the combo. If you find happiness with a .535 and some patch or other, I bet you'll keep right on using .535's for the duration, and maybe adjust your patch thickness one last time around 1700 shots further down the road.

 

[Gene L]

I replaced the rear sight on my GPR with a primitive one from TOW. Easy enough and the fit was just right.

 

[Louisk]

Thanks! Good to hear from someone with loads of real experience. I thought I was using .018 patches, but after reading your post I went and took another measurement on my material (prewashed pillow ticking) and with just a little squeeze on it with the mic it came out to .015. Sounds like thicker patches might be the thing to try next. I'm not sure if the local fabric store sells thicker stuff or not. I like the idea of cutting my own patches so hopefully they do.

 

[mooman76]

It doesn't necessarily have to be pillow ticking. A good strong tight weave natural fiber. A thin cotton denim will work or see if they have mattress ticking, it's thicker. Also Pocket drill cloth is good.

 

[jethro224]

I agree with Brownbear on the thicker patch. Mine likes 80 grains of 2F under a .530 ball with a .020 patch but I'm not near the 1700-2000 mark yet.

The primitive rear sight is a big improvement for me over the adjustable sight that came on the rifle. The blade might be a bit thick for pinpoint accuracy but it is easy to see in the woods, works for deer, and the wide rear sight groove of the primitive sight works well for me with the stock front blade. Be aware tho, the factory primitive sight doesn't fit the factory dovetail without some light peening.

 

[BigAl52]

Which front sight did you order for yours from TOW

 

[pab1]

Which front sight did you order for yours from TOW

I've put their FS-TC-HB-TH sight on a couple of them. I've been happy with that sight. I did have to file the base of the sight to fit the dovetail. I also put one of their cast floral petal sights on one rifle and like it. They offer two versions of this sight and I don't recall which one I used. It had to be filed to fit also.

 

[pab1]

I pulled them out and took a pic. I actually used that sight I mentioned the part number of on three of them. The one at the top is the first one I did years ago and I didn't fit it as good. None of them are fit perfectly but I improved with each one. They work well for me. I still need to sight in/file the third one down. I haven't used that gun since changing the sight blade.

 

[Louisk]

Thanks again, guys. Looks like quite a few options for changing the sights. I'm hoping that trying thicker patches well make for acceptable accuracy, then start fiddling with the sights. Hopefully I'll get things dialed in soon. Losing daylight fast here and am working on borrowed time before my shooting spot gets snowed in!

 

[BigAl52]

Thanks Pab1. I wondered how that floral sight worked as I have looked at it. I have a 54 cal flint and like you I cant understand the need for that thick front blade. Seems like alot of these gun manuf. seem to think we need a dozer blade out front. Al

 

[pab1]

Thanks Pab1. I wondered how that floral sight worked as I have looked at it. I have a 54 cal flint and like you I cant understand the need for that thick front blade. Seems like alot of these gun manuf. seem to think we need a dozer blade out front. Al

No problem. I agree. I can't understand why they would put so much effort into making a quality gun and include that sight with it.

 

[rusty]

Pab,can you show a picture of the rear sight you put on your rifles..d

 

[Kapow]

I put the primitive sight provided by Lyman on my Gph. I prefer it for hunting. It is a lot easier to see than you'd think at 100 + yards. Very chunky sight makes acquisition in a hunting situation a bit quicker for me but every set of eyes are different.

 

[pab1]

Pab,can you show a picture of the rear sight you put on your rifles..d

I didn't try to blue the finish on any of the cast sights. I did brown the bottom one on the GPR kit I built. I believe at least a couple of them are TOTW part number RS-KC-16. I have one of these still in a bag that I'm pretty sure I ordered as an extra. The rear sights also had to have their bases filed to fit the dovetail on the barrel.

 

[hanshi]

My rifles all got less accurate over the last 10 years cause I know it twernt my shootin'. On top o' that, my pants have been shrinking around the waist. :rotf:

All seriousness aside, as I went to .022"/.024" from the .015" patching, my accuracy AND velocity improved in all of them. Two had radius rifling .016" deep and really needed the thicker patches. The square cut .010" groove bores also benefited greatly. I'm a firm believer in fairly tight loads.

 

[Powerkicker]

The primitive rear sight that came with my gpr was a nice fit right out of the box. No filing or peening was required. Mine also does not appear to like .010 patches.

For those struggling with the front sight, try painting it white. It has made the sight picture pretty nice.

 

[Kansas Jake]

I carry a white chalk in my shooting box and if I'm in a situation where it is hard to see the black front sight I just chalk it. It stays on pretty well and is easy to touch up. If the situation is better for a black sight a damp finger will rub the white off the sight.

 

[Louisk]

Thanks for the help! I think I may be getting this thing dialed in a bit. I measured the patches I was using at .015 so I went and bought some precut pillow ticking patches which were labeled to be .018. I went out last night and fired a bunch of shots with mixed results. It seemed like the effort to seat the ball with the new patches was the same as it was with the new ones so I got out the micrometer and found the new patches and old ones were the same exact thickness. I guess it's just a matter of how hard you crank down on the mic. I cut out some patches today from some denim material that I measured to be around .020. I made it to the range later on this evening and with the little daylight I had left I shot a group that was considerably tighter than what I'd been doing before. I fiddled a bit with the stock sights and I think I can make them work reasonably well, at least good enough for this year. It feels good when things seem to start working after a little effort. Again, I REALLY appreciate the great advice.