Lapping works

[jtmattison]

I had reported before the not so impressive accuracy of my new GPR.
I lapped the barrel and the groups tightened considerably but were still not impressive.
I worked the barrel some more, but this time with just 0000 steel wool and oil.
I got her driving tacks!
I shot yesterday and after tinkering with loads I found a .018 ticking patch lubed with homemade bore butter and a .530 RB over 80 grains of 3f was the best load of the day.
Three shots, swabbing between shots, were touching each other at 50 yards with the stock buckhorn sights.
I love this rifle.
I see many more years of pleasure coming with this rifle.

Huntin

 

[SquirrelsaurusR]

What did you lap it with the first time?

 

[jtmattison]

I lapped with turtle wax rubbing compound, 50 strokes followed by turtle wax polishing compound, 25 strokes.
It didn't totally take care of the patch cutting so I did about 25 strokes with 0000 steel wool lubed with Rem-Oil and that did the trick.

Huntin

 

I had reported before the not so impressive accuracy of my new GPR.
I lapped the barrel and the groups tightened considerably but were still not impressive.
I worked the barrel some more, but this time with just 0000 steel wool and oil.
I got her driving tacks!
I shot yesterday and after tinkering with loads I found a .018 ticking patch lubed with homemade bore butter and a .530 RB over 80 grains of 3f was the best load of the day.
Three shots, swabbing between shots, were touching each other at 50 yards with the stock buckhorn sights.
I love this rifle.
I see many more years of pleasure coming with this rifle.

Huntin

Did you try a .535 ball wrapped with a bore butter lubed ticking patch and a 80 grains of 3f? That's all I ever use in "Lucifer".

 

[jtmattison]

I hit the range with the new GPR again this weekend.
Boy is she shooting sweet.
80 grains of GOEX 3f with a .018 patch and .530 ball is her sweet load.
I shot the center out of my target at 50 yards off the bench.
8 shot group, or should I say hole was about 1 1/2 inches.
I am extremely pleased with this rifle.
I have a .535 RB mold on it's way to me.
I will try her with the larger RB this weekend and report the results.

Huntin

 

[harryo]

The rubbing compound probably wasn't abrasive enough. I had the same accuracy problem with my new .54 GPR caplock. I couldn't get it to shoot under 5" groups at 50 yds. It was also cutting patches. I used a wet patch and some white jeweler's rouge to lap my barrel. It didn't take much and I could feel it smooth out after probably 16-18 strokes. I also took a triangular file to the rear sight and opened up the notch a bit and painted a yellow dot on the front blade for a much better aiming reference.

It is now a very good shooting rifle. I just went out today and shot consistant 1.5-2" groups at 50 yds, off of cross sticks. Lapping the barrel certainly improved the accuracy.

Mine likes .535 cast balls, .018 pillow ticking patch, Lehigh Valley lube and 80-100 grains of Goex FFg.