GPR 1 in 32 or 1 in 60

[Dan_T]

I have decided to get a Lyman GPR in .54 cal. I will be using it for deer hunting and target shooting. My question is should I get the hunter model with a 1 in 32 barrel twist for conical bullets or the 1 in 60 twist for round balls? I am interested in the best accuracy and the best deer load. New member and first time poster thanks in advance for your help.

 

[jbtusa]

I would recommend the 1:60" for round ball. The rb has plenty of whoomph for all game in the lower 48 and it is very accurate for your target shooting.

 

[BrownBear]

I'm betting for the combo of target and deer you'll get the most use and satisfaction out of the 1:60, that is, unless you live in open country requiring shots much past 100 yards. In my experience with the 1:32, it will shoot round balls well up through about 80 grain powder charges, but the groups start opening up as you go higher. I don't shoot game past 100 yards, so I don't need the conicals, but that's me and my hunting grounds. I'd sure slap on the 1:32 and shoot conicals if I was shooting longer.

Other than that, you're down to personal taste and politics in choosing between them. The 54 caliber RB is plenty for deer through elk, and edging into moose. And depending on the individual rifle and the ranges shot, a 1:60 might be more accurate target shooting with RBs than the 1:32.

A couple of things to recognize about target shooting: Some matches might require you to use RB rather than conicals. And especially this: If you're not going to cast your own conicals, cost will run you out of house and home. Conicals cost roughly 5 times as much as round balls. Not even a slight issue when you cast your own, but something to think about if you plan to shoot lots.

 

[Cogburn]

I recently got a GP Hunter in .50 caliber with the 1 in 32 ROT. It is super accurate with round balls as long as I keep the powder charges below 80 grains. It is easier to load too because of the shallow rifling meant for the conicals. I am extremely happy with it for RB shooting as well as the conicals. I hunt in a very wooded area where a 75 yard shot is a long one however.

 

[Trench]

I recently got a GP Hunter in .50 caliber with the 1 in 32 ROT. It is super accurate with round balls as long as I keep the powder charges below 80 grains. It is easier to load too because of the shallow rifling meant for the conicals. I am extremely happy with it for RB shooting as well as the conicals. I hunt in a very wooded area where a 75 yard shot is a long one however.

What would you say your definition of "super accurate" is with an 80gr charge? I wouldn't have guessed it would shoot that well with that charge. Also, what thickness patch do you use? My father also owns a GPH and would probably be interested.

 

[Cogburn]

Well, I was speaking of hunting accuracy, not target accuracy. I would say that I can consistently hit a 2 by 4 on edge at 30 yards. This is the first Lyman GP that I have owned and I am well pleased with its performance. Now most of my practice shooting is done using 50 grains of powder not 80. It is a pleasant load to shoot. I use pillow ticking from Wal-Mart for a patch. I have a 25 grain spout on my measure because I hunt with a .32 some also. I use one measure full for the .32 rifle. Two measures full for the .50 cal GPHunter when practicing and plinking and 3 measures full for hunting deer.

 

[BrownBear]

I'll chime in to help define "accurate" too. Our two fast twist rifles are both 54 cal. In both 30 grains of 3f will keep all shots touching at 25 yards, and darned near touching at 50 yards. That's ideal for mushing heads on snowshoe hares. Accuracy is as good or better at 50 grains. On a good day my wife can pretty much shoot a ragged hole from a sitting position at 50 yards. I aint that good!

At 80 grains of 3f, groups start opening up to 1.5"-2" at 50 yards. Haven't taken loads higher in either rifle because that's plenty accurate and plenty powerful for deer hunting. But it's not going to win any matches.

On the other hand, the 1:60 barrels keep producing ragged-hole 50 yard groups as you raise the charge past 80. No need to shoot hotter for deer, but the extra accuracy is there if we decided we needed faster.

 

[longcruise]

My question is should I get the hunter model with a 1 in 32 barrel twist for conical bullets or the 1 in 60 twist for round balls?

.54 and round ball is more than adequate for deer, elk, etc.

RB is more versatile and can be downloaded for "mushing" (i love that one brownbear ) rabbit heads or uploaded for elk, etc. In between there will be a great accuracy load for targets.

The RB gun is much more economical to shoot.

The RB gun is much more comfortable to shoot. The recoil of a .54 conical is pretty stiff and can be downright painful with the GPR butt plate shape.

If you must shoot conicals, go with the .50 or even a .45 if possible. They will kill with authority and not be as hard on the shoulder.

Anyway, that's my view on it fwiw.

 

[BrownBear]

The RB gun is much more comfortable to shoot. The recoil of a .54 conical is pretty stiff and can be downright painful with the GPR butt plate shape.

Boy, did I ever do Dan a disservice in forgetting that point! I'm here to tell you that 450 grain conicals on top of 120 grains of 2f will redefine your understanding of the laws of physics. Dang! They make 12 gauge 3" slug load seem like patty cake.

I don't have any problems with the crescent buttplate on the GPR because I put it out on my arm a little rather than in the socket of my shoulder. But you get that much powder moving that much bullet, and that rifle is coming BACK!!!!

I figure the biggest reason inline shooters use sabots is they aren't man enough to shoot full sized conicals on top of their 150 grain powder charges. It's easy to demonstrate that the heavies shoot flatter for long range, so the sabots and light bullets are a weenie out to dodge recoil.

 

[Tom Compton]

A .54 pure lead ball will flatten to over 3/4" at it's widest point and pass thru most any game in North America.

I see no reason to buy or build a .54 that will most likely only shoot conicals accurately, use more lead and kick more. If you already own a 1/32 twist .54, see if you can get acceptable accuracy w/ the round ball.

Define acceptable accuracy? I'll hunt with 3" groups at 100 yds but prefer 2". Hard to measure that at 50 yds 'cause the paper is too tore up.

TC

 

[Otter]

A .54 RB will do the job on any North American game (with the possible exception of Grizz) if you do your part. For me, I always considered "hunting accuracy" and "target accuracy" to be the same . . .

 

[dyemaker]

Conicals are slower starting out than roundballs but maintain their velocity much longer than roundball because roundballs shed velocity really fast. I agree with BrownBear, it depends on how you hunt. A roundball it seems, would shoot flatter up to a distance than a conical would but soon loose it's fizz after that. You do the math.

I always wondered about this... shouldnt the twist rate of conical barrels be respective to caliber too? The .50 caliber GPH and the .54 caliber GPH both have a 1:32 rate of twist... Odd. I imagine that recoil may be uncomfortable with the .54 GPH and the curved buttplate but I really don't know. If they offered the .54 caliber roundball rifle with a 1:66 rate of twist that would be nice.

 

[Dan_T]

Thanks everyone for all the great information. I never even considered the recoil.
I would be shooting targets mostly at 50 yards, most shots at deer where I hunt would be under 60 yards but I would like to be able to preseant a good kill shot out to 100 yards. It sounds like the round ball would fit the bill.

 

[nkbj]

Wasn't there a post a while back saying that Lee REAL's were shooting OK in a GPR?

Maybe look at this from the other direction...
Maybe a GPR round ball barrel will handle a conical of the proper design. A 530 rb weights about 225grs. 54REAL's weigh 300 and 380. That's a bunch of lead, probably all we (as in including my GPR) should try to chunk out of 15/16" barrels.

On the other hand, minies have a nose heavy stabilizing effect built into them and they don't need much twist. Now, the designs commonly produced probably wouldn't be worth trying. But, a thick skirted paper patched hollow base might work. Maybe.

So, maybe a 54 GPR round ball barrel gives all the flexibility you could expect out of 15/16". Doesn't mean I'd wanta loose my Ed Rayl fast twist but maybe my slow twist deserves another look.

 

[PreglerD]

As it is our goal to shoot traditional I will recommend the GPR with 1 in 60" ROT. The .54 PRB has enough power to bring down any game moving around in the USA. You can go up to charges of 130 grs bp and shoot them with good accuracy out to 150 yds.

Regards

Kirrmeister

 

[cowpoke1955]

Dan,
Let's not forget cost. Round balls cost so much cheaper than conicals. Even if you cast your own. I have two .54 GPRs, one cap and one flint. With a .530 ball, pillow ticking patch lubed with Ballistol oil and 80 grains of FFg Goex I get one ragged hole at 50 yards. I once got a 3/4" group at 100 yards using 90 grains of FFg. These GPRs will do it if we do our part. I was shooting 380 grain Lee REAL bullets one day. Had a nice, dark black and blue mark the shape of that butt plate, not to mention the pain. I can shoot round balls all day and hardly feel the recoil. The 1 in 60" twist barrel is the only way to go :thumbsup:

 

[BrownBear]

Wasn't there a post a while back saying that Lee REAL's were shooting OK in a GPR?

Maybe look at this from the other direction...
Maybe a GPR round ball barrel will handle a conical of the proper design. A 530 rb weights about 225grs. 54REAL's weigh 300 and 380. That's a bunch of lead, probably all we (as in including my GPR) should try to chunk out of 15/16" barrels.

On the other hand, minies have a nose heavy stabilizing effect built into them and they don't need much twist. Now, the designs commonly produced probably wouldn't be worth trying. But, a thick skirted paper patched hollow base might work. Maybe.

So, maybe a 54 GPR round ball barrel gives all the flexibility you could expect out of 15/16". Doesn't mean I'd wanta loose my Ed Rayl fast twist but maybe my slow twist deserves another look.

I've got both the molds and have shot them fairly extensively in my 54 GPR. The 380's are just about hopeless. Yeah, I could get 2-3" groups at 50 yards when I launched them at max velocities (ouch), but by 100 yards they wouldn't stay on the target paper consisently.

The 300's fared a lot better at both ranges, but for 100 yard game, I'm going to call them marginal. Groups were 6-8", and only that good when you really stiffed up the powder charge.

BTW- Both shot best with a lubed felt wad between them and the powder.

And while I'm BTW-ing, you really need to cast perfect bullets, and with all those driving bands it means very hot lead and a good hot mold. I didn't start dropping perfect bullets till 20 or so had passed through the mold. And even after that, you need to inspect them closely and reject any with flaws.

 

[David W.]

would choose the 1:60 twist. Like previously stated, it will shoot a hollow base minie with good accuracy and is perfect for the prb. A slower twist is also better when the rifle gets a little fouled.

 

[nkbj]

"The 300's fared a lot better at both ranges, but for 100 yard game, I'm going to call them marginal. Groups were 6-8", and only that good when you really stiffed up the powder charge."

I'd love to see what the velocities were. The REAL is actually kinda blunt nosed compared to a round ball. At 300 grains for the REAL, I can't help but wonder if the 225 grain round ball wouldn't be going just as fast out to 100yds.

 

[ebiggs1]

Being a TC guy, I may be wrong but doesn't Lyman make availible seperate barrels for the GPR? Pretty reasonable too I remember. You could have both!