Lyman Great Plains .54 Caliber

[mark/wi]

The 1 in 60 twist is called Great Plains Rifle
The 1 in 32 twist is called the Great Plains Hunter.

Mark

 

[Hntr79]

Tim,

It was indeed the sportsman's warehouse near Memphis, TN. My dad was there and asked if I needed anything. I told him to look and see if they had any traditional smokepoles left, and he told me about the Lyman. This was on Saturday, but they may still have some left. I don't know when the actual store close date is.

 

[Mulebrain]

You done good!

I have the same rifle in flinter, and you will like it!

I am surprised employees didn't gobble them up.

Well luckily for you they didn't :thumbsup:

 

[grimjaw]

I wanted to piggyback on this thread and ask a question. I have a GPR .54 with the slow twist. I'm thinking about getting the hunter barrel with the faster twist, but I'd rather have it in .50 for a larger choice of conicals. (I don't have room or time to cast my own .54 yet). Will the .50 GPR Hunter barrel fit in my existing .54 GPR stock without any modifications?

Much thanks for any info.

jm

 

[Lonegun1894]

it will fit. They are both 15/16".

 

[cowpoke1955]

Heck, hop in the car and take a drive to this Sportsman's Warehouse in Memphis and just buy a GPH. It's not that far :haha:

 

[zrifleman]

Mark---Look again! The GPR can be purchased with either the 1-66 twist RB barrel or 1-32 twist conical barrel in 54 cal. Midway has replacement barrel kits either way. I know, I just replaced one. The Hunter has a shorter barrel with 1-48 twist.

 

I bought a Lyman Great Plains rifle approximately 8 years ago. The hammer didn't line up with the nipple. I sent it back to the factory and the problem still was not corrected. That rifle now rests over the mantle of my fireplace. I then went and had John Bergmann build me a custom Hawken with a Davis lock and a Green Mountain barrel and that rifle shoots like a dream!

 

[cowpoke1955]

Mark is right. The Great Plains Rifle has a 1 in 60" twist barrel and the Great Plains Hunter has a 1 in 32" twist barrel. Both barrels are 32" long and 15/16" across the flats. Lyman does make a 1 in 48" twist, 28" long barrel for the Trade Rifle, but not for the Great Plains. You can get a 1 in 66" twist barrel from Traditions or Pedersoli, but not Lyman.

 

[Otter]

Z -

Just looked at Lyman's website to verify . . .
GPR (.50 or .54) - 15/16" x 32" barrel. 1:60 twist
GPH (.50 or .54) - 15/16" x 32" barrel. 1:32 twist
Trade Rifle (.50 or .54) - 15/16" x 28" barrel. 1:48 twist

The GPR and GPH barrels are interchangeable.

 

[Gametracker]

Is this a good rifle, and does anyone have any load suggestions for me? I plan to use it for cow elk and mule deer in Colorado this year.

I killed two 10-point mule deer (4x4's for you westerners) in the last 3 years with the Lyman GPR. I have the .54 cal. 1-60 barrel. Killed both with 100 grns. Goex and .535 RB., which I find to be very accurate at 100 yards. One buck dropped in 30yds, the other larger buck dropped in his tracks. I wouldn't trade this gun fer nuttn'.
I struggled with what I thought was the "hammer/nipple mis-alignment" problem at first. Thought I wasn't seating the cap firmly enough, but was still experiencing the occassional cap failure. Finally learned the problem was my fault. Seating the cap firmly isn't the same as seating it squarely. Now I've learned to twist the capper while I'm pressing it to make sure the cap doesn't sit "cocked" on the nipple. Problem solved.

 

[greatplains]

I'm a little late responding to this post, but here is my experience with my GPR. 430g T/C Maxi-balls shoot like laser beams with 82.5g of 2f Triple 7. I've shot 3 shot groups at 100 yards that were 1.5" or less several times with a tang mounted aperture and fiber front sights. Keep in mind mine is about 19 years old. A couple of years ago I was curious on what rate of twist the barrel had, (couldn't really remember what the specs were way back when) and checked multiple times by drawing a patched cleaning jag and measuring the revolution of the rod. Came out to close to 1:48" every time. Is that correct or is it actually 1:66? Doesn't much matter, it's just a great rifle....

 

[Hntr79]

I shot her for the first time today. Not that accurate, but I noticed that the patches were burning up. They were just cotton patches, so I bought some pillow ticking patches to try that. Hope it fixes the accuracy problem.

 

[mykeal]

You will not achieve the rifle's accuracy potential until you've shot at least 100 rounds through it. And the patches will be cut for the first few dozen rounds also.

 

[45-70cannon]

Don't have that problem with mine. However you will find that sometimes you have to take the nipple out retap that hole, make sure the threads are there to hold the nipple in place. I actually blew the nipple port and all out of the last GP 50 I had. Took it over to Len Day for rework and he explained it as those #$%@^&### italians can't tap a hole worth manure. the threads are too shallow and the results is the nipple port blows up in your puss. He's right as now that i fixed the gun, someone else owns it!
My 54, on the other hand has a nipple port that only goes on one way,(needs retappin too) but I use CCI caps and I've had no problems with it.
She shoots a 100 grain charge of Triple 7 and a 535 ball with a .015 lubed patch. Breaks skeet at 100 yards (powders em) and blasted right through the buffalo I shot last year.
LUV that rifle, I surely do!

 

[Hntr79]

Why do the patches cut in the first couple dozen rounds? Is it because the barrel is rough inside?

 

[Zonie]

When a barrel is manufactured the cutting tool that creates the rifling grooves leaves a very sharp edge where the sides of the rifling grooves meet the bore.

This very sharp edge will easily cut cloth patches and when it does, the fiery powder gasses will burn thru the gashes.
This always leads to very poor groups.
Shooting the rifle over 100 times eventually wears the sharp edges off of the grooves so the patch cutting goes away and accuracy improves.

Wrapping a piece of steel wool around a cleaning jag and running it up and down the bore many times will also remove these sharp edges.

Do not use valve grinding compound or similar abrasives to dull the edges of the rifling.
These are much too abrasive and they can damage the rifling.


Personally, until now I haven't heard of anyone complaining about the threads in the nipple port of a Lyman caplock gun. I also have not heard of nipples blowing out unless someone had previously over-tightened the nipple or cross threaded the nipple when he/she was installing it and literally ripped the threads out of the breech block.
If such damage is ignored and a new nipple is then installed there is a good chance that it will blow out. IMO, This isn't the fault of the manufacturer though.

As for retapping the nipple hole I can not recommend that anyone try it.
It is much too easy to get the tap started into the hole slightly cocked (cross-threaded). It the tap is cross-threaded into a perfectly good hole and then is forced into the hole it will totally destroy the existing threads which will ruin the barrel. Once this happens there is no low cost cure. Buying a new barrel or having a new breech plug fitted by the factory is about the only answer.

 

[45-70cannon]

Actually there is an answer and you don't have to buy a new barrel either. If you are a machinist you will know how to retap the hole, of course, but incase you try it and something happens, what you do next is take it to a machine shop and they will redrill and tap the hole to a slightly larger diameter and when you do this, look up the next size nipple port that you want and tell them. They will do it for you.
Leonard did that for me, and I am an ex machinist and all (way, way bak about 200 years ago)
but Leonard has the machine shop.
Don't let anyone bullsnot ya into thinking the only way out is a new barrel. that's hogwash and they iz bein lazy or stupid!

 

[Zonie]

Stupid he says? Well, I've been called worse.

Pay a machinist to drill and tap a new threaded hole? Now why didn't I suggest such a thing? :hmm:

The nipple for a Lyman Percussion gun is a M6 X .75 thread.

Now, as any machinist would know, in order to have a quality thread, the minor diameter (tap drill) of the new thread must be as large or larger than the major diameter of the old thread.
If it isn't, the major diameter of the old thread will prevent the forming of threads which comply with the new threads minor diameter resulting in partial threads.

A M6 X .75 thread has a major diameter of 6mm or .2362 inches.
That rules out a 1/4-20 with its .207 maximum diameter internal thread minor diameter and it rules out a 1/4-28 with its .220 maximum internal thread minor diameter unless the user is willing to accept a half ass thread for his guns nipple to screw into.

I guess the user could have the machinist make a special thread for one of Dixies oversize nipples like the Dixie .270-28 or larger but taps for these threads don't come cheap and I'm sure the user would end up paying for the tap plus the machinists labor.
It also would force the user to use these special oversize nipples from now on.

Don't get me wrong. These oversize nipples are sometimes the only fix for damaged barrels so they do have a place in our world.

Yup Richard, I guess I'm stupid for not thinking of this neat way to save a barrel that would not need saving if the owner hadn't followed some questionable suggestion about retreading a perfectly good nipple hole in his barrels breech.

Have a good day.

 

[Harold1950]

I don't know if this is possible but as suggested, take it to the machine shop and see if they can possibly weld the old nipple hole up and then redrill and retap it.......don't know but may be possible to do, don't know how cheap though