Great Plains Rifle Problem

[Klaus]

Hi Gent`s

i need your experiences for this issue

a good friend of mine has a Great Plains Rifle .Cal 50 since some times
Prefered Load 60 - 70 Grains Wano PP Powder .490 Ball and the correct Patchdiameter for years
The Rifle shoot`s and hit`s reliable for a long time.
Since around a half year this Rifle is not able to center hit 5 Shoots in a acceptable Group anymore.The Bullet Impacts are all over the Target
We have checked all possibiles,Bedding, Wedges Stock, Screws ... and clean and polish the Barrel carefully , polish the Muzzlecrown also .The Barrel inside shines bright an no hints about rust damage or any other failures to find.
There is a smooth loading from shoot to shoot no stocking no jerking.
Have you ever heard about a Barrel that has lost his accuracy this way ?

Any Idea :surrender:

thx for your help

Klaus

 

[BrownBear]

Have you ever heard about a Barrel that has lost his accuracy this way ?

In my experience with several Great Plains Rifles, it's actually expected. As the barrels smooth or wear, they eventually require a slightly thicker patch. It's so common that I expect it- usually after 300-500 shots and again at around 1500-2000 shots.

I started my last 50 cal with .490" balls and .015" patches, and at the 500 shot mark had to increase it to .018" patches with the same diameter ball. At 2000 shots I went to a .495 ball and .015" patch.

One other possibility- If your friend has increased the amount of lube he's using in that slick bore, accuracy can suddenly drop. You might try using just a little less lube before changing your patch.

That's the "easy" explanation and solution. I can't imagine what else could be happening, so I hope it works for you.

 

[Critter Getter]

Your friend might try replacing the nipple on his gun. Greg

 

[Maven]

Another possibility is the adjustable rear sight if you're using it rather than the primitive one: the adjustable one doesn't always retain your settings, hence erratic shooting.

 

[ohio ramrod]

So true! the adjustable sights have been known to "loosen up" and give very large groups due to movement of the sight with each recoil.

 

[Steve-ALA]

Had a GPR for years. I learned that it liked a very tight patch / ball combo. The tighter, the better my groups.

 

[Boomerang]

Yep, could be several things:

Make sure sights are tight.
Try a new nipple.
Use a tighter patch.

In that order.

 

[ZUG]

If the rifle WAS shooting good groups and all of a sudden it started doing poorly I bet dollars to doughnuts that the nipple has gone south :hmm: -- replace it -- shoot it :v .

 

[Zonie]

I can't say it's true from first hand experience but I've heard, several times, from several different people that a muzzleloading rifle barrel can be too smooth. If this happens, accuracy goes down.

There's the story of a guy at Friendship who's favorite, long time, rifle lost its accuracy.
An old time shooter talked to him about the problem and told him he could fix it.

He then loaded a powder charge and poured a bit of sand into the barrel and fired it downrange.

Supposedly, according to the story, the guns great accuracy instantly returned.

Now, I'm not suggesting that anyone should try roughening up their bore like that but maybe running a piece of very course (120 grit) sandpaper down the bore on a cleaning jag might help it.

Then again, maybe not. :hmm:

 

[mooman76]

Check the fired patches to see what shape they are in. Could be old and deteriorating or weak. Reading the patches tells you allot. I have heard of this before and no single answer is correct. Someone has a ML for years. Have a favorite load that has been a tack driver and now it no longer works. Usually it's something they changed either without realizing or thought it wouldn't matter.

like stated sometimes after a gun gets wore in from many years of use moving up to a thicker patch or slightly larger ball helps bring it back.

I just remembered another. When the nipple hole wears over time and gets bigger, accuracy drops off. Cheap and easy fix and it's always good to have an extra.

 

[bob308]

I have a great plains rifle got it cheap.it would not shoot or so they said. got .490 balls and .015 patches with it. friend told me to go thicker on the patches. cut the groups in half. then he got me to try .495 balls. groups got smaller. the final thing was a new hot shot nipple. that turned it into a match winner.

 

[rdstrain49]

If your friend doesn't use a muzzle protector for loading and cleaning he may well have worn the last couple of inches of the bore with the ram rod. The only fix for this is to cut a couple inches off the barrel or re-barrel it. Much more common condition than you might expect.

 

[Klaus]

To all who answered me i have to say a big thx

we will follow your advises step for step and see what happen finally.

coming back with the results for interrest

thx from Germany
Klaus :hatsoff:

 

[BrownBear]

coming back with the results for interrest

Please do so! Such an exchange of experience is the strength of this great site! :thumbsup:

 

[Artificer]

Klaus,

I have forgotten how many times over the years I have seen percussion rifles or rifle muskets "all of a sudden" lose accuracy and the result was a worn nipple. This from competitions using round ball rifles and minie' ball rifles.

When I was the Team Armourer for the U.S. International Muzzle Loading Team, I most strongly recommended each shooter put a NEW nipple in his or her rifle every new shooting season AND for those in International Competition, to have a second nipple that was already test fired as well. There can be some differences in nipples that sometimes will result in different accuracy even when new. In International Competition, you just don't take chances on something as inexpensive as a new nipple each year with a back up nipple.

In 1998, one of our best Women Shooters was almost in a panic during practice before the World Championships began. She was firing an original underhammer percussion rifle that was extremely accurate, normally, but was stringing shots all around in practice. I pulled the nipple and it was noticeably worn, so I put a new one in. It came right back to Dead On accuracy. Later that evening, I asked her why she had not changed her nipple at the start of the shooting season as I had suggested. She told me he had put a new on in the year before or the year before that and since it was shooting fine, she didn't change it. I just shook my head and told her that was exactly why I suggested putting a new nipple in before we traveled to the matches.

She was MOST fortunate after spending all that money to travel and stay in the UK, that the nipple "went down" during practice and not during the match.

Gus

 

[Klaus]

Hello Gus,

it appears unbelievable that this little part of the Gun wil have so a huge effect on target accuracy.
but as i wrote before we will change the Nipple and check step by step

will keep you updated

thx Klaus :hatsoff: