Lyman GPR

[Chris Cade]

just bought a gpr from my uncle ($60) but the barrel is pitted pretty bad. only able to hold a 10" group at 50 yards using .490rb and .010 and .015 patches. any thoughts from the knowledgable? i'm thinking of buying a .54 cal barrel as i've read these make a better balanced rifle. thanks

 

[Prairieofthedog]

Mechslasher,If you cannot get acceptable accuracy out of it then you have to explore options.I have both the .50 and .54 GPR and the .54 is a better balanced gun.You could get your .50 rebored to .54 by a barrel smith for $130-$140.Or a Green Mountain barrel retrofitted to drop in your GPR.You can buy Lyman GPR drop in barrels too,but I think they are pushing $250[you would have to check that price].Or you can just buy a good used .54 GPR for $250-$300 and turn your present one into a smoothbore LOL. Good Luck.

 

[Chris Cade]

i was thinking smooth bore but now i'm leaning toward having it rebored. can you give some info on locating a barrelsmith to have it cut to a .54?

thanx

 

[Hawkwood]

I've had some luck tightning groups by lapping the bore and dressing the crown as needed. Also the powder charge used can have a dramatic effect on group size.

 

[StewartLeach]

Mech:

Don't give up yet on that barrel. You may be able to bring it back to acceptable performance. First, try applying a good penetrating oil and letting it soak for a week, then brush and patch well. Kroil is the best penetrant around, but any of the common hardware store products will work well. Might try repeating this two or three times.

Next up the aggressiveness ladder is a really good scrubbing with JB, RemClean or one of the other abrasive cleaners. Work the goop into a tight fitting patch, run ten strokes, turn patch over, ten again. Clean out bore, repeat several times. Typical white cleaning patches aren't tough enough for this- use twill patches, old blue jean knees, etc.

As a last ditch effort, try fire lapping, which involves firing abrasive impregnated bullets down the barrel using moderate charges of fast burning powder. I've had very good results from this process, including a 50 cal Renegade barrel I thought was hopeless. See post # 661182 on this Forum, wherein Marmotslayer gives details.

White Fox

 

[ebiggs1]

If you have not tried multiple loads, you don't know that it won't shoot because of pitting. :hmm: A good barrel can shoot 10 inch groups with the wrong load. :shocked2:
And most importantly, you must have a steady rest to test for grouping. :thumbsup:

 

[S.Kenton]

Just went through that with my 50 cal.GPR BARREL...I had similiar groups with a pitted barrel.I scrubbed it out and used a " valve lapping" compound.. also toothpaste, steel wool wrapped around my jag and a few other tricks.. After I got done scrubbing the barrel I flushed it out with brake cleaner and a cloth patch, let it dry and ran an alcohol saturated patch down the barrel.Then headed out to give her a try, I also made some changes to my load based on the advice I got from this forum. First, I changed my .010 patch to a .020 patch went from a 90 grain ( goex fff) charge to a 70 grain. I got my shots to group MUCH better after the work I did.. then even better after I changed the load. Now,at 50yrds I am shooting 2 1/2 inch to 3 inch groups from a rest.. at 75 I am about 4-5 inch now. I did replace the barrel with a new one and am happy with the results...I too am interested in re-boring my "extra" barrel to a .54 cal.

 

[Prairieofthedog]

Mechslasher,The 2 Barrel Smiths I hear the best reports about are Ed Rayl and Bobby Hoyt.Ed Rayl,Box 91,Gassaway, West Virginia,Phone#304-364-8369.I don't have Bobby Hoyt's info.

 

[ryoung14]

I'd drop that pitted tube like a hot potato. New New Lyman barrels are available from Midsouth Shooters supply. Scroll down to see the selection: http://www.midsouthshooterssupply.com/department.asp?dept=MUZZLELOADERS&dept2=PARTS

they're not cheap, but they'll turn that GPR into the .54 you want. Bought a spare .54 barrel for mine a couple of years ago. It came with a tang. Prices have gone up substantially in the last couple of years. Think I paid around $140.

 

[FRJ]

I've seen lots of pitted barrels shoot just fine. Im surprised that no one asked what powder and charge is being shot I've sent you an e mail on that. Just clean the barrel and shoot what I told you about way before you start spending money on stuff thats real expensive and you may not need.Frank

 

[bob308]

bob hoyt is in fairfield pa.