Patch blowby

[Hawken12]

I am the proud owner of a Mike Brooks 62 cal rifle.She is a beauty...Thanx Mike.
Now that the weather is breaking and I can get to my shooting hole.
I have started the process of sighting in,the fun part,marrying me to the rifle.I want to get the best out of it,to do the Builder and the owner proud on our new journey together.
OK long intro,sorry
the problem I have is patch blowby,I am using 18 thou denim patches...20 thou is too tight and 15 too loose.
Using a 600 ball in a 620 barrel
with lube (wonderlube) and spit patch,with a hard card between powder and ball,still getting burntout sections in patches!!!
I have a 3x2 group so far with 65 grain of 2f powder at 25 yard.not good .
I am reluctant to continue til I solve the burnout problem

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How,in your opinions do I eliminate the blowout ?

 

[Wes/Tex]

Two quick thoughts...can you post a couple pictures of the patches, that might help us understand what's happening better. There is usually some burning on any patch, how much and where tells more about what's really going on. Might also try something like a bees wax/olive oil mix for lube. Have had better results than with most commercials products. Also, there's no reason you can't put more than one card or even a thicker fiber wad like is used in shot loads. Allowing the fiber wad to soak in oil/grease then letting them dry out may solve a lot of the burning problem. This is also one of he reasons I switched to leather patches. Besides compressing better than cloth, they don't burn or smolder like even lubed cloth patches can. I'm sure you'll get some other tips as well. Keep shooting and having fun!

 

[curator]

Sometimes new barrels have sharp lands that will cut the patch and cause blow by.This may be the problem, and if so, some shooting will smooth the bore and the problem will go away. If it is sharp lands, you could use some 000 steel wool on a bore brush and smooth the lands a bit. "Flitz" or #400 valve grinding compound on a tight patch wound around a nylon bore brush will do the same thing. Alternately get a heavy rubber mallot and a sturdy short starter and go with the 20-thousandths denim.

 

[Billnpatti]

Are you using new denim material? Are you washing it before using it? Used denim will vary in thickness depending on from where on the pants or shirt it comes. New denim will be the same thickness everywhere. If you don't wash it, it will have sizing in it and not compress into the rifling well nor will it absorb lube well. Any of these things can possibly lead to patch blowby. You can use felt wads between the ball and the powder. 1/4 inch thick Duro-Felt is very good stuff. Take a sheet of it and spread your lube on it like buttering toast. Then put it in the microwave for a few seconds to melt the lube into the felt. When it cools, use an arch punch of the correct size to cut a nice snug fitting wad. Load this on top of your powder and it should eliminate any blowby.

 

[Ken Cormier]

My thoughts are that it just a new barrel. Give it a hundred rounds or so to get broken in then if still doing it I would worry about it. Until then I would just enjoy the new gunne. Just my .02¢

 

[Ft. Jefferson]

I routinely need to use the split off half of a fiber wad over the powder with charges over 65gr-3fg. At ignition, i believe the fiber wad begins to tear apart as it wraps around the back of the ball and fragments then seal the bore and protect the patch.

 

[Hawken12]

here's a coupla patches

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both sides,all just turned over,Thanx Peter
not sure why but they is sideways,like I git sometimes...

 

[Hawken12]

am thinkin same thing ,here ,just hesitant on runnin 4 OO wool down my prize girl,how many wipes do you think...

 

[Hawken12]

it is new denim,and washed twice

 

[Hawken12]

I do have felt wads presoaked ,was goin there next ,as was thinkin that the hard card is not filling in between the lands enuff

 

[Patocazador]

Go with curator's suggestion and use Flitz or JB Bore Paste with a tight fitting patch saturated with it. Between 50 and 80 strokes ought to do it.
Then try working mink oil into the patches so it's between the fibers. These steps should improve your situation.

 

[Wes/Tex]

Judging by the small cuts around where the ball and patch contact the bore ant he muzzle, I'd say you're still dealing with a sharp edge at muzzle and possible along the groove/land edges. Would recommend you try the steel wool or compound method to just take the sharp edges off. Be sure to follow Bill's advise about washing denim unless it's from a well washed source.

Also surprised to see as much scorching on those patches if you've using a wad between them and the powder charge. Got to think the use of an extra card or the fiber wad may be worth your time to try. Keep plugging away. It'll work out!

 

[Hawken12]

one thing I did try,I put a loose patch first then loaded a ball and patch, and voila no burnt patches,repeated and again,no burning,that was at the end of that session.
Tis why I went with hard card,next time out.still got the holes,which gets me thinking the card isn't filling the grooves,or patch is getting cut on the way down the bore.
Gave the bore 50 wipes with 4 OO steel wool this morning...will have to wait ...Mother Nature has decided winter is not over yet...2 inches and blowin.
Thankyou gentleman,for your tips ,will post results,soon

 

[Rifleman1776]

Those are cuts. Just keep shooting to wear sharp edges of rifling. Or do the 0000 steel wool thing. You won't harm anything. BTW, IMHO, ditch the wads. Your ball may be too small. I know it's a hassle, and expensive, but try larger balls. e.g. .605, .610. I believe you will get better results all the way around.

 

[Hawken12]

Ha ,the girlfriend says the same thing...lol.Did the steel wool,down the bore.So when this storm lets (4 inches now) will be trying just a patch,first to see if the wool did the job.I'd prefer ,not using the wad ,firm believer in the KISS method,however each gunne ,likes what they like and if I have to go to the wad,its not too big a deal.
Thanx for your observation
Peter

 

[lcharles]

two things caused me grief with a .54 ball shooter
load was 120 gr FF with calico patch and moose milk
1) that wrecked the patches = I put down a backer patch over the powder and fixed that but was still getting flyers - one or two every string of ten
2) my patches were too small!! looked ok - I loaded careful but I went back to the start and cut a patch on the muzzle to get the right size - that thing was huge compared to what I was using! seems that now and then the ball was tipping a bit as I rammed and those little patches were losing contact one side of the ball. I say put a ball flush with the muzzle and cut a patch then pull it - if youve not done that you will be surprised how very large the patch is for your rifle.

 

[lcharles]

I second the steel wool idea - have done that with a number of rifles (includes a couple of neglected ones that got spotty in the bore) wrap fine steel wool round a bore brush to fit as tight as you can get then I use brasso on it to polish the bore - make sure you dont ding the crown with your rod is all

 

[Rifleman1776]

ball was tipping a bit as I rammed and those little patches were losing contact one side of the ball

How do you tip a ball???
Too small a patch can be a problem. Cutting at muzzle is way to prevent that.

 

[ohio ramrod]

Have you tried an over powder wad?. I find a leather wad between the powder and patched round ball can work wonders to prevent blow by and burned patches. :idunno:

 

[Hawken12]

I can see(tipping),if using precut patches and the patch is not centred on the bore.However I am cutting at the muzzle. I did the steel wool ,this morning,didn't feel anything catching as I slid up an down.But sharp and clean would not do that either I believe.
Just waiting now ,I think storm has passed(6 inches,now)
Going to try just 18 thou spit patch first and see what happens,hopefully ,no cutting.
If there is cutting ,have 20 gua wads to put over powder(hard cards did not seem to work)