Patch question

[OB OBrien]

I'm wondering if these patches are normal or would they be considered burnt? If so whats needed to correct the problem.

Here are two of the patches from my last session at the range. 50 cal, coned GM 1 in 70 barrel, 75 grains fffg Goex. .17 pillow ticking patches with a 7:1 Ballistol lube.

Top picture is the powder side, bottom picture is the ball side.

Thanks for looking. OB

 

[Vaino]

Three possible problems...looks like some gas leakage and might require a thicker patch or larger RB, slight cutting of the patch which requires more shots or a bore rubbing w/ green "Scotchbrite" and lastly more of or a different patch lube.....Fred

 

[paulvallandigham]

i agree with Fred. you have evidence of patch cutting, but its not clear whether you have a sharp land edge( or burr), or whether the tear is from gas cutting. I suspect you may have a sharp edge at the Crown of the muzzle, because the front edge of one of your lands has a burr on it.

I would check it in good light, carefully, and even test the crown, by using a strip of fabric, and a ball to push down into the patch, then pull the strip and ball out, and examine the strip for holes. That will identify and locate the the source of the problem( the sharp edged land).

If you are not cutting that patch on your crown, then you need to run a patch carefully and slowly down the barrel, with a tight fit on a jag( I often use two patches, both lubed, in front of my jag, so that I get a very tight fit) to determine which land has the burr, or sharp edge on it that is doing the cutting( tearing).

These patches appear to be pre-cut, and they are on the small end of sizing. You have to be absolutely accurate in centering the ball in the patch, before running it down the barrel. If you get the gas "ring"( that dark sooty ring around the ball) too close to an edge, you can suffer "Edge failure" and have the patch torn out there.

I recommend buying patch fabric at your local fabric store- take a micrometer, or caliper to measure the thickness, as not all fabric are the same. Look for mattress ticking rather than pillow ticking,which is usually thinner, or denim, or pocket drill, or linen.( or buy strips of material sold by the suppliers, like Dixie GWs, Track, October Country, etc.)

Cut strips and cut your patches at the muzzle to avoid the problem of getting too off-center with your ball when starting the ball and patch into the barrel.

If you buy fabric by the yard, you will save a lot of money.

Wash the fabric at least twice, to remove the "sizing" that is put into the material at the factory. Then iron the fabric, and cut your strips to width. Roll up the strips, hold them with paper clips, or rubber bands, or string if you have to be HC, and you are ready to go. All you need is a good, RAZOR SHARP, patch knife to cut the patches at the muzzle. :thumbsup:

 

[OB OBrien]

Hi Paul; The patches are either pillow or mattress ticking. They mike out at 017 after washing. They are cut at the muzzle with what was once a razor sharp knife. (I need to sharpen that puppy.) That might have caused the fraying around the edges. Am making new patch strips as I type. While at the range I noticed some of the balls loaded easily with just thumb pressure. Others were quite tight and needed the edge of the ball starter to seat them flush. I even noticed one ball had a sprue on it. All these balls were new out of the box, Hornady swaged balls? Think I'll take a closer look at them. Will also take a look for a burr. Oh by the way this is a new GM barrel. Has only had maybe 50 to a hundred shots through it. Keep tuned, i'll get back to you all. Thanks OB

 

[OB OBrien]

Hi youall, it's me again.
I checked the crown with a pair of old panty hose, no burrs.
Sharpened the patch knife.
Checked the rifling, with a bore light, no burrs or inconsistencies.
Found 14 out of 39 Hornady swaged 490 balls had sprues on em.
Opened a new box of Hornady 490 balls, Most all of them had sprues.
Guess I need to pay more attention to the quality of the bought balls and my loading methods.
Will be back to the range tomorrow and lets see what happens.
Thanks again for you alls help.
Regards
OB

 

[paulvallandigham]

If you have a case tumbler, or vibrator, throw those balls with the sprues into the device, without the cleaning compound(grit) used to clean casings, and let them bump against each other for an hour. The sprues will be gone and the balls will be pretty well rounded. ( always check, and throw any that aren't round back for more "bumping" against each other. ) For Target work, it helps to sort balls by weight, too.

Something is tearing those patches. Fred gave you the three possibilities. I would still run patches down the bore, slowly, to FEEL for burrs. New barrels all need breaking in time- at least 200 shots-- and even Green Mountain barrels, as good as they are, need it, too.

 

[ebiggs1]

I am leaning towards, Fred's suggestion of lube. You may just need to use more instead of changing it.
I would bet it isn't a burr or sharp, whatever, in the bore. I also doubt this will hurt your accuracy very much unless you are a competition shooter.