Got my first traditional this week the GPR Hunter in .50cal. What ball size should I get for this rifle? I know all bores are different and I need to "slug" the barrel to measure it. But if you push a slug down how do you get it out since you cant remove the breach plug? Thanks guys.
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My GPR ball size
- Thread starter Quigley
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rafterob
62 Cal.
Try a .490 first. The handbook with the rifle should give a recommendation. Unless the one that comes with the "Hunter" only lists conicals.I've personally never slugged my barrels and really never found a reason to. I think the easiest slug method I have heard of is to take a large teardrop lead sinker, insert narrow end into barrel and pound it in with a mallet till you are sure it is into the rifling , then remove it. Hopefully someone here with the GPH will chime in with useful hands on experience.
You slug a closed breech barrel with Cerrosafe, a chamber casting alloy.
It melts at a low temperature (approx 160 deg F) and when it cools initially it's slightly smaller than the bore dimensions so the slug can be easily removed. After about an hour of cooling it returns to the bore dimensions so you can get an accurate measurement.
I make a 'plug' using a large swab on a wire loop and some patch material, place it in the barrel a few inches down, pour in the melted metal, let it cool the prescribed time and pull out the plug with the slug in front of it.
The directions and timing information for Cerrosafe are included with the alloy. It's reusable. It's available from Brownell's: Cerrosafe link
It melts at a low temperature (approx 160 deg F) and when it cools initially it's slightly smaller than the bore dimensions so the slug can be easily removed. After about an hour of cooling it returns to the bore dimensions so you can get an accurate measurement.
I make a 'plug' using a large swab on a wire loop and some patch material, place it in the barrel a few inches down, pour in the melted metal, let it cool the prescribed time and pull out the plug with the slug in front of it.
The directions and timing information for Cerrosafe are included with the alloy. It's reusable. It's available from Brownell's: Cerrosafe link
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A Q&D way to "slug" a muzzleloader bore is to use a pure lead fishing sinker, the tear-drop shaped ones with the little brass ring at the small end. Pick one that's just over bore size and use a pipe a little smaller to tap it 1/8-3/16" into the bore. Grab the brass ring and pop it back out. Done.
Based on my own history with GPRs, I'm guessing that .490 balls with .015 patches are a good place to start. After the bore smooths a bit (firing 100-200 shots), you're likely to find it loads .018 patches easy enough to be convenient, and accuracy will jump. NIB, GPR barrels are a little tight or rough for my tastes with the .490/018 combo. Some guys will advocate .495/.010 combo, but that thin patch is even more susceptible to patch cutting in a new Lyman bore. You're likely to be shredding some patches even with .015, but live with it till you get past that 100-200 shot boundary and the resulting bore smoothing. It's likely to shoot pretty darned well right off the bat even when shredding patches, but it gets even better once the patches start behaving.
Based on my own history with GPRs, I'm guessing that .490 balls with .015 patches are a good place to start. After the bore smooths a bit (firing 100-200 shots), you're likely to find it loads .018 patches easy enough to be convenient, and accuracy will jump. NIB, GPR barrels are a little tight or rough for my tastes with the .490/018 combo. Some guys will advocate .495/.010 combo, but that thin patch is even more susceptible to patch cutting in a new Lyman bore. You're likely to be shredding some patches even with .015, but live with it till you get past that 100-200 shot boundary and the resulting bore smoothing. It's likely to shoot pretty darned well right off the bat even when shredding patches, but it gets even better once the patches start behaving.
longcruise
70 Cal.
The short and sweet answer to slugging is "don't bother". Slugging won't reveal the formula for the correct ball and patch. The only thing it will tell you is the preise meausrements of the bore and the depth of the grooves.
But, we know it's a .50 cal and that it will shoot with a ball reanging from .490 to .500. Ghettogun set you on the right path suggesting that you simply start with .490.
Gather up three or four prospective patch materials, a box each of .490 and .495 balls and head to the range. Start with the smallest ball and the thinnest patch and work toward the largest ball and the thickest patch. Use heavy charges of powder. "Read" your patches as you shoot. Don't bother seeking accuracy, just check your patches. In fact, there is no reason to post targets during this process. The combos that show good patch survival are the ones that are good prospects for your final selection.
This all takes some time and expense but it is worthwhile in the end.
Little Wattsy
69 Cal.
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I have yet to find a need to "slug" a muzzleloader barrel. You can use a .490 or a .495 ball (or a host of connicals) I would start with the .490 and try patches in .015, .018, and .020.
Work up your loads at 25 yards. Play with powder charges (in 5 grain increments) and patch ball combination looking for your BEST 3 to 5 shot group. Then sight in.
My Lyman likes... the .018 patch.
Work up your loads at 25 yards. Play with powder charges (in 5 grain increments) and patch ball combination looking for your BEST 3 to 5 shot group. Then sight in.
My Lyman likes... the .018 patch.
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Wattsy said:
Same here.... bofum.
Wrap it around a .490 ball and all is well for me. But both those guns were tough loading when new, so I dropped down to .015 for the breakin.
BTW- My rifles are absolute tack drivers with the 35 grain charges of Goex 3f or Pyrodex P I use for small game. Ragged hole groups at 25 yards and darned near that at 50 yards.
The funny thing though, they're just as accurate with 60 grains of either powder and with the 90 grain charges I use for hunting. POI is essentially the same for all three out to 50 yards, and I only see a difference in POI at 75 yards and beyond. I've got the rifles sighted in dead on at 75 yards with the 90 grain charge, which puts them dead on at 25, slightly high at 50. With the 75 yard sight-in they're 2-3" low at 100. That's really handy to be able to shoot with so many charges and so many distances without changing the sights. Dandy, as a matter of fact. :thumbsup:
BTW- I agree on the bore slugging. It's a cute little exercise and dirt easy with the fishing weight, but it doesn't tell you anything you need to know to get a GPR shooting well.
Little Wattsy
69 Cal.
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Mark Lewis said:
:shocked2: This "logic" escapes me... :rotf: :rotf: :rotf:
Ummmmm, comfirmed it with the wife; Smaller is NOT gooder. But I GUESS you could try a .445 ball? :haha:
I have to agree that slugging a bore is not necessary to finding an accurate load. With the availability of only two or three ball sizes, for each caliber, a coupla boxes of balls is all that is needed, along with a few different patches of different thickness', and a coupla different lubes.
Track or Eddie MAy might even sell you 25- 50 balls of each size available for your bore dia, however, even oversize balls will load and shoot well with the right patch, lube, and powder.
IMHO, a .490 is a good place to start.
Assuming the depth of rifling is .010, a .015-.018 patch is a good place to start, though a .020 patch might be better.
For patch lubes, Try plain old spit for your first range session. Just place a coupla patches in your mouth and suck on them while you are preparing to load. Get 'em wet so's they will wipe the bore with each shot.
God bless
Track or Eddie MAy might even sell you 25- 50 balls of each size available for your bore dia, however, even oversize balls will load and shoot well with the right patch, lube, and powder.
IMHO, a .490 is a good place to start.
Assuming the depth of rifling is .010, a .015-.018 patch is a good place to start, though a .020 patch might be better.
For patch lubes, Try plain old spit for your first range session. Just place a coupla patches in your mouth and suck on them while you are preparing to load. Get 'em wet so's they will wipe the bore with each shot.
God bless
Little Wattsy
69 Cal.
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Mark Lewis said:
I somehow think that if those sizes worked "best" then you would be able to get them and there would also be standard .025 and .030 patches to go with.
So unfortunately im gonna have to call :bull: on this one. :wink:
I notice that you said you have the "Hunter" model.
That barrel is designed for shooting slugs and to get the best accuracy from it with a slug you really should measure the bore.
The slug should be .002-.003 smaller than the bore for best accuracy.
A patched .490 or .495 roundball will work, a the others have said but because of the fast twist and shallow depth of the rifling grooves it may not give the best accuracy with large powder loads.
We don't discuss plastic things on the forum because they were pretty scarce in 1864 (like none?) but some of those expensive plastic things might work better than a patched roundball.
That barrel is designed for shooting slugs and to get the best accuracy from it with a slug you really should measure the bore.
The slug should be .002-.003 smaller than the bore for best accuracy.
A patched .490 or .495 roundball will work, a the others have said but because of the fast twist and shallow depth of the rifling grooves it may not give the best accuracy with large powder loads.
We don't discuss plastic things on the forum because they were pretty scarce in 1864 (like none?) but some of those expensive plastic things might work better than a patched roundball.
"A patched .490 or .495 roundball will work, a the others have said but because of the fast twist and shallow depth of the rifling grooves it may not give the best accuracy with large powder loads. We don't discuss plastic things on the forum because they were pretty scarce in 1864 (like none?) but some of those expensive plastic things might work better than a patched roundball." (Zonie)
A couple of things to add to the above, as I have some experience with a fast twist rifle that shoots bullets surrounded by "plastic things." First, you may find your GPR Hunter is sensitive to powder granulation: Try FFg if you have it. Second, fast twist rifles WILL shoot patched RB's, but you have to limit your powder charge to 50 0 60 grs. FFg. Lastly the larger ball (.495"), thinner patch (.010") didn't work at all in my rifle. It was much happier with a .490" RB with a .018" patch. Hope this helps!
A couple of things to add to the above, as I have some experience with a fast twist rifle that shoots bullets surrounded by "plastic things." First, you may find your GPR Hunter is sensitive to powder granulation: Try FFg if you have it. Second, fast twist rifles WILL shoot patched RB's, but you have to limit your powder charge to 50 0 60 grs. FFg. Lastly the larger ball (.495"), thinner patch (.010") didn't work at all in my rifle. It was much happier with a .490" RB with a .018" patch. Hope this helps!
Tom Compton
54 Cal.
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Lyman's Great Plains Hunter
This is a special version of our Great Plains rifle with the hunter in mind. Called the "Great Plains Hunter", this new model features a fast, 1 in 32" shallow groove rifled barrel. It's ideal for shooting the many types of modern projectiles available to today's black powder hunter, such as Lyman's own 'Shocker' series of bullets and sabots. The Great Plains Hunter has all of the high quality features of our Classic Great Plains rifle. It is also also pre-drilled and tapped for the new 57 GPR receiver sight for the Great Plains rifle.
Notice PRB not mentioned in the above description only "modern projectiles". 40 gr or so should be about the best PRB load in the 1:32 shallow groove GPH barrel. Any more acceleration than that produces will probably strip the rifling and shoot knuckle balls which are OK at 25 yards and maybe not bad to 50 but purely sucks at >50 yards.
Tight ball and patch combinations for the forth coming round ball barrel will work best to fill the deep groves, seal the pressure and impart adequate spin on the ball. Charges >70 gr are required to maintain ball velocity greater tham the speed of sound to 100 yards. As a projectile of any kind transitions from super sonic to sub sonic, the turbulance causes unpredictable changes in direction.
IMO if you plan on shooting 30-40 gr loads no more than 50 yards, don't waste money on another barrel.
This is a special version of our Great Plains rifle with the hunter in mind. Called the "Great Plains Hunter", this new model features a fast, 1 in 32" shallow groove rifled barrel. It's ideal for shooting the many types of modern projectiles available to today's black powder hunter, such as Lyman's own 'Shocker' series of bullets and sabots. The Great Plains Hunter has all of the high quality features of our Classic Great Plains rifle. It is also also pre-drilled and tapped for the new 57 GPR receiver sight for the Great Plains rifle.
Notice PRB not mentioned in the above description only "modern projectiles". 40 gr or so should be about the best PRB load in the 1:32 shallow groove GPH barrel. Any more acceleration than that produces will probably strip the rifling and shoot knuckle balls which are OK at 25 yards and maybe not bad to 50 but purely sucks at >50 yards.
Tight ball and patch combinations for the forth coming round ball barrel will work best to fill the deep groves, seal the pressure and impart adequate spin on the ball. Charges >70 gr are required to maintain ball velocity greater tham the speed of sound to 100 yards. As a projectile of any kind transitions from super sonic to sub sonic, the turbulance causes unpredictable changes in direction.
IMO if you plan on shooting 30-40 gr loads no more than 50 yards, don't waste money on another barrel.
Quigley said:
If you have not yet ordered your round ball barrel, I would suggest www.midsouthshooterssupply.com for the best price.
You might consider getting one in .54 caliber.
If you got the primitive rear sight in the box with the GPH, put it on the roundball barrel. The sight picture is better with the primitive sight and you'll be allowed in more matches. :thumbsup:
I really like my GPR with both .50 and .54 barrels. They're great guns. Accurate and reliable. Have fun with yours. :hatsoff:
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