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Author Topic: Lyman Great Plains  (Read 5534 times)

Offline Hylander

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Re: Lyman Great Plains
« Reply #30 on: November 19, 2017, 11:35:57 PM »
Thanks guys,

Rob: How tight is the breech plug, how hard to pull it apart ?

Offline RobD

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Re: Lyman Great Plains
« Reply #31 on: November 20, 2017, 06:13:35 AM »
investarms breech plugs are the easiest of all the offshore trad ml's to work on, but they will require 4 things.  a 15/16" breech socket (ebay for about $30 - it has a proper cut out to clear the bolster on a cap gun), a large long wrench to grab the socket (i use an 18" reed corp, but most any long and large pipe wrench will do - goodly leverage is needed), a padded vise that's securely mounted in order to hold the barrel *tight*, some anti-seize lube for the threads when putting the breech plug (or bolster or nipple or touch hole liner) back into the barrel (permatex at any auto store).  before removing the breech plug a witness mark line is drawn on the bottom of the barrel, that scribes over the plug and barrel.  these are reference marks to properly align the plug and barrel when it all goes back together after cleaning and greasing.




















Offline Hylander

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Re: Lyman Great Plains
« Reply #32 on: November 20, 2017, 07:20:08 PM »
Thank Rob.
Looks like you have a nice vice clamp for the barrel, are those available for sale somewhere ?

Offline RobD

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Re: Lyman Great Plains
« Reply #33 on: November 20, 2017, 07:30:49 PM »
that's a rice barrel company magnetic octagonal vise clamp set ... $40 worth every penny!  also add in the $30 rice plug wrench for traditional non-patent breech plugs.

http://www.ricebarrels.com/products.html

the 18" reed corp flat jawed wrench is $70 ... also worth every penny!

http://www.millsupplies.com/Reed-RCORP-4-12-Smooth-Jaw-Wrench_p_53333.html

all that hardware is worth the pennies for me because i remove breech plugs and other such items quite often, and definitely not just my own.   8)


Offline Hylander

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Re: Lyman Great Plains
« Reply #34 on: December 07, 2017, 11:39:07 PM »
Rob:
Do you have a link for the 15/16" breech socket.
I can not seem to find one.

Offline RobD

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Re: Lyman Great Plains
« Reply #35 on: December 08, 2017, 06:30:00 AM »
can't find any listed on ebay other than the 13/16" plug wrench (might wanna contact that seller and see if he has a 15/16") ... https://www.ebay.com/itm/Breech-Plug-Removal-Wrench-13-16-Thompson-Center-Seneca-Cherokee-Custom-Made-/282331965477?hash=item41bc4be825

not sure about this one, it might be a 15/16" - https://www.ebay.com/itm/VINTAGE-THOMPSON-CENTER-BREECH-PLUG-WRENCH-FOR-1-INCH-BARRELS-/401449339177?hash=item5d783ec929

Offline Hylander

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Re: Lyman Great Plains
« Reply #36 on: December 08, 2017, 11:56:46 PM »
can't find any listed on ebay other than the 13/16" plug wrench (might wanna contact that seller and see if he has a 15/16") ... https://www.ebay.com/itm/Breech-Plug-Removal-Wrench-13-16-Thompson-Center-Seneca-Cherokee-Custom-Made-/282331965477?hash=item41bc4be825

not sure about this one, it might be a 15/16" - https://www.ebay.com/itm/VINTAGE-THOMPSON-CENTER-BREECH-PLUG-WRENCH-FOR-1-INCH-BARRELS-/401449339177?hash=item5d783ec929

Thanks,
emailed seller, no response.

Offline prairie dog

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Re: Lyman Great Plains
« Reply #37 on: January 17, 2018, 06:24:37 PM »
Those GPR rifles are fairly dependable guns.  Keep the patent breach cleaned (I use a 38 caliber pistol brush) and they fire every time.  It seams all the 50 calibers I know like an 80 grain charge of 3-F.  Mine shoots tight groups with a 495 ball and a tight patch.  The deer hate it.
Steve Sells

Offline Uncle Russ

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Re: Lyman Great Plains
« Reply #38 on: February 01, 2018, 04:51:14 PM »
This short dissertation is under the heading of FWIW..... :bow

I have only owned 3 GPR's over my lifetime of shooting, with the last one being a flintlock "kit", that I put together, maybe 12 / 15 years ago, many of the old-timers here will remember my raving about that particular rifle, and the new unexpected accuracy I was getting at 75 yds..
The GPR, IMHO, was at the time the "most often seen" new rifle on the Ranges that I shot on, and all for good reason.

Back in the day, sometime before Import / Export increases, Yankee Dollar re-evaluation, Trade agreements, and 9/11, had all happened, this Lyman Import represented a pretty good investment for a "one of the better shooting, Hawken looking, rifles" on the market at at right around $200 it was a good deal.....and, with all the changes of times in between now and then, it may very well still be, even at today's sometimes flat-out ridiculous prices.

About the 2nd GPR I ever owned, I got the opportunity to take a close look at the inside of the barrel through a friend who owned a nice bore-scope at the time.
What I saw inside that barrel was not at all what I had expected.
Instead of the nice smooth, shinny, lands and grooves I had expected to see, it looked more like a strip of land that had been fresh plowed, then cleaned-up with a disk and harrow before planting.....not at all what I had expected, and compared, to a early model T/C barrel.
 
But that "look" did not appear to have any effect at all on the accuracy of those rifles, not back then, and not even now.

Fast forward until today and we find ourselves with more "custom" Rifles, and stand alone barrels, available to many in the market.
Many of those barrels are polished, shine like new money, and are often praised as state-of-the-art barrel making.
Not that many years back I came into possession of my own bore-scope and I have closely examined many rifle barrels since that time.
I've not only looked at the dozen or so rifles I personally own, but that of friends, neighbors, and those just curious. 

I have come to the conclusion that the "remarkable" accuracy that the GPR quickly became noted for, was due, in most cases, to its Twist Rate, and had little to nothing to do with how nice that barrel looked inside, rather how well it performed.

Back in the early days of T/C, back when a lot of their rifle parts was sub-contracted out to then up and coming new, and sometimes unheard of manufacturers, they too released quite a few barrels with a Twist Rate other than 1:48.

A few of those older barrels are still around, and they are now demanding much more than than the original cost of the entire rifle when new, often up to 4 or 5 times more!
Is that because they are "Pre-Warning, Pre-Model, but bear the T/C Stamp"? Or is it due to someone's rifling other than T/C?
 
Many of those barrels were marked with that Manufacturers "stamp" in some unobtrusive place on the barrel, and that's when all the problems started.
The new bean counters at T/C decided that practice was "counter productive" and betrayed the brand.....completely disregarding the new sales figures and upswing in popularity,  those sub-contractors were discouraged from adding their "mark or small stamp" to those barrels, and the practice of producing a 1:48 ROT went unabated for years.....accuracy of those 1:48 barrels was, of course, good.
But when it came to the lowly round ball and patch, at many different distances they could barely keep up, still yet they excelled in the "longer than diameter" projectiles that was quickly becoming popular.

The T/C story I just related is not "documented".
Supposedly a fire, sometime in the mid 1990's, destroyed all or most historical records regarding the  T/C Muzzleloader.
This story has come to me, over many years, from old-timers that actually worked for T/C for a lot of years.
Up until the time of Corporate Resettlement / Redistribution, when those employees lost not only their jobs, but their investment in the company too.

Is this just a story of disgruntled employees, feeling they got the short end of the stick?
If that were true, then employees of Rice, Green River of Utah, Green Mountain, Douglas, and other employees of "then new and upcoming barrel makers" who had once worked as T/C sub-contractors, would know nothing of their story....but that's just not the case.

Why is all this important?
-Many folks are interested in such things because they own one, or both of these rifles, and both represent a hallmark in affordable rifles for our own hobby of Traditional Muzzleloading.
-T/C is credited with being the one manufacturer that created the entire Muzzleloading craze that took place shortly before the Bicentennial in the 1970's. They did that with dependable, well made Muzzleloaders, that looked a lot like the fabled Hawken Rifle.

Uncle Russ...

 
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Offline RobD

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Re: Lyman Great Plains
« Reply #39 on: February 01, 2018, 05:21:00 PM »
excellent info, uncle russ  :bl th up

none of the offshore rifles will have lapped and honed barrels, all will be in-the-rough to, so to speak, to varying degrees.  as russ alluded to, the more important key to a good barrel is the twist rate as compared to the bore, and the depth and type of rifling.  as barrels are loaded and shot, the bullets and patches are doing the lapping.  some folks run a jag with steel wool to start the lapping process.  almost all offhsore guns are using the standard square bottom .008" rifling.  patch 'n' ball guns will have a 1:60 twist and rifles for conicals will have much faster 1:32 twist - these are both in the GPR or GPH lyman series, guns with 32" barrels.  the lyman trade rifle exhibits the compromise 1:48 twist that allows both balls and maxi bullets or lee REALs. 

the last GPR kit i bought was this past year, a .50 flinter, with a 1:60 twist for patched balls.  i didn't even build the kit let alone shoot it, and sent the barrel to bobby hoyt.  he reamed it out to a .54 and we collaborated on the the twist and rifling - it now sports a 1:56 slightly faster twist (due to the short 32" barrel length) and with a .012 deep radius bottom set of grooves.  the radius bottom helps with loading and fouiing control.  it took a few months for bobby to get to my project and complete the barrel, and then for me to finish it up, so it didn't become a shooting gun 'til late december.  well worth the added $150 barrel charge (bobby's reamed other barrels for me).  it'll get baptized this spring.  can't wait for the winter to depart!  :wave