Third outing with my GPR flinter

[daveol]

I went to the range yesterday armed with a bottle of Moosemilk and a supply of fresh made Moosemilk treated pillow ticking patches. I also lowered my powder charge to 70gr. 3f., and used .530 roundball.
Thanks Stumppy, and all those who responded to my post last week GPR .54 flint experiences & question #132945 - 06/24/05.
:hatsoff:
This time out I was also able to locate two or three of my patches.
They were in perfect shape.

On all of my prior targets, including those from my two previous trips to the range all impacts were Low & Right. After drifting my rear sight to the left, my lateral alignment now seems fine.
Although I expected my shots to continue to hit Low, I am a bit perplexed as to why the vertical stringing. All five shots were in near perfect horizontal alignment, but were strung vertically over a three inch line.
I shot from the bench sandbagged, at 50 yards. The only reason I can think of for protracted string would be having an inconsistent cheek weld to the stock altering sight alignment, due to the un-natural hunkered down position while sighting the sandbagged rifle. If so, I would also have expected this to also affect lateral alignment as well.
Here is a link to a scan of my target:

I have around 125 -140 shots through the barrel so far. I am wondering if it may be time to bring a file with me to the range next time.
I have searched the archives and read up on how little filing is necessary to bring up the POI. As calculated by the formula contained in the archives, .011666 of an inch off the front sight per inch of elevation at 50 yards.

Any comments or tips will be appreciated.

Dave

 

[Rebel]

Be sure to take some tape or something, i use a piec of thin cardboard with a notch cut in it for to fit over the sight. This will keep you from messing up the bluing on your barrel WHEN the file slips. It isn't if it will slip. Believe me, it will. ::

 

[AeroE]

Two things to try to eliminate the vertical stringing -

- make sure the forestock or barrel rests at exactly the same point on the front bag for every shot. It's common for a shooter to let the gun creep to different spots from shot to shot.

- Try a different powder charge; this gun doesn't look tuned to me. Try increasing and decreasing the charge. Make sure your barrel keys are not wobbly, and mark them so you can always remove and reinstall them in the identical location and orientation.

You can also try shooting free recoil and so on, but you really need to develop a consistent hold that is practical for field use.

 

[cptleo1]

When bench resting.

vertical stringing is often breathing related.

take a breath
hold it
align the sights
let a little out
hold it
squeeze

Let some one else shoot it
and see if it does the same thing

Also check the wedges tension
they should be about equal.

Different padding on the bench might
be a good thing to change

You are almost there

Be patient :thumbsup:

 

[Bob J]

Thanks to Birddog6's advice, I just started shooting square patches in my .54 GPR too. :thumbsup: Whatcha cuttin' them with and what dimensions?

 

[wilded]

Be sure and wipe between shots and see if that effects the stringing. I had a rifle that would shot one ragged hole as long as I wiped between shots. As soon as I quit wiping between shots it would start vertical stringing. :m2c:

 

[Runner]

It's obvious from the patches that he is swabbing between shots. Verticle stringing can be caused by having the patches too wet also. They change the powder load each time that way by wetting part of it.

 

[wilded]

Then run a second dry patch.

 

[Java Man]

Or less lube on the shooting patch.

 

[daveol]

Thanks for the responses so far

It's obvious from the patches that he is swabbing between shots. Verticle stringing can be caused by having the patches too wet also.

Yes i have been wiping, and no the patches are not wet. Actually I soaked the material in Moosemilk, let them dry, then repeated the soak - dry process before cutting the material into patches. When I used the patches at the range they felt dry with a hint of dry-sliperiness when run between thumb & index finger.
For wiping I used a more moist patch; again, not wet.

make sure the forestock or barrel rests at exactly the same point on the front bag for every shot. It's common for a shooter to let the gun creep to different spots from shot to shot.

I have a sneaking suspicion that using the bags front & rear to rest the rifle and the associated un-natural shooting position (hunched over the sandbagged rifle) may be part of the problem. I spend more time fluffing and repositioning sandbags between shots than I do wiping and loading.
Next time out I may try using just front sandbags, and build them up to a height which affords a more natural shooting position.

- Try a different powder charge; this gun doesn't look tuned to me. Try increasing and decreasing the charge. Make sure your barrel keys are not wobbly, and mark them so you can always remove and reinstall them in the identical location and orientation.

Keys and barrel are tight.
First time out I was shooting 80gr. Was able to make some 2" groups low and right.
Second time out I bumped it to 85gr, and didn't wipe between shots. It shot low and right before things got nasty.
This time out upon advice from the board, I lowered my charge to 70gr., changed to Moosemilk & pillow ticking, and wiped between shots. I also drifted the sight to bring the POI to the left.

I just started shooting square patches in my .54 GPR too. Whatcha cuttin' them with and what dimensions?

When I was at Walmart buying the pillow ticking I picked up a Fiskars 65mm rotary cutter. Eleven or twelve dollars if memory serves me correct. I lay the material on a piece of 2x4 with a scrap piece of lattice (whatevers handy) as a straight edge and run the cutter along to make strips about 1-1/4

 

[Bob J]

Thanks Dave,
I have bought the same ticking at Wally World and that's how I'm cutting them, as Birddog 6 suggested.

Believe your comment about the sandbags may be true; I've just started foregoing the rear bag for reason you've stated. Am now crossing arms and supporting buttstock in a more natural shooting position and it seems to be working well. According to the range officers, this is how the best shooters shoot.

 

[Zonie]

Daveol: Ain't ole Stumpies Moose Milk somethin? It war worth him gettin kiked 4 times ta get a sample ta base his fourmula on!
Yup, .012 off tha front site O yer GPR will move tha group 1 inch up at 50 yards.
Korse, .012 missalinment of tha front site rite or left will move yer group 1 inch rite or left too out thar at tha targut.

Someday sumones gonna kum up wit ah mettel tube wit sum eyeglasses gluued inside it an sum sites painted on um so's all ye wil hav ta doo is ta luk thru it an see that buls I an pul tha triggar, but it ain't a gonna happin in hour livetimes! ::

 

[Stumpkiller]

Shucks.

Weren't so bad onst I figgured out the ones without the antlers was the females and they're the ones to milk. Though, I did get a few moose phone numbers.