Breaking in a new barrel?

[Thekingd93]

I acquired a 32 inch green mountain barrel .50 caliber 1:66 unfired. I heard from a fellow shooter/co worker that I'll have to shoot about 100 patched round balls to break in the barrel because of how sharp and new the rifling is inside the bore. Just curious to other people's thoughts on this subject.

 

[renegadehunter]

It has been reported that some barrels cut patches when new.
I personally would shoot it and see what kind of accuracy you get before making a decision. If accuracy is good I wouldn't even bother looking for spent patches. If accuracy isn't real great, then gather some spent patches and see if they show cutting/tearing. If they do and you're a patient fella and have the time, put a couple hundred shots through it and see if groups improve and patches look better. If you want to speed up the process, then some polishing of the bore will do so. I personally like Montana X-treme Bore Polish.
I have an even better idea. Send it to me and I'll check it out for you (great find by the way, I'm envious!)

 

[Stykbow]

Shoot it first and see how it does. It may be fine without any help. If it does, I just put some 0000 steel wool around my bore brush and scrubbed it about 100 strokes. It’s not super aggressive, but it worked for my rifle. You can always run a scotchbrite pad thru. Or you can just shoot the devil out of it. Either option will smooth it out if it needs it.

 

[M. De Land]

I acquired a 32 inch green mountain barrel .50 caliber 1:66 unfired. I heard from a fellow shooter/co worker that I'll have to shoot about 100 patched round balls to break in the barrel because of how sharp and new the rifling is inside the bore. Just curious to other people's thoughts on this subject.

Yeah, my .45 cal cut patches for about 50-75 rounds but no more. I don't believe you can do better than a GM barrel personally. I prefer them to any other because of the quality and the fact they are actually made of barrel quality steel instead of the normally used 12L14 leaded steel that most muzzle loading barrel maker use.
I have install quite a few of them in making black powder cartridge rifles as well muzzle loaders.
I ran plug gauges and a bore scope in mine before building a SMR from TOTW and it had one of the most consistent bore diameters of any barrel I have checked.

 

[zneufeld]

I had to polish my GPR with about 100 strokes of a Scotch-Brite pad, fixed my fouling issues and cut patches.

 

[necchi]

a fellow shooter/co worker that I'll have to shoot about 100 patched round balls to break in the barrel because of how sharp and new the rifling is inside the bore.

Yeah, it's about 100 rounds, but it's not really about "sharp new rifling",, magically changing into a great load combo.
It's about the time the shooter needs to figure out how to best use a new quality barrel.
So yeah, shoot it, a bunch. You'll be very happy you did.

 

[Stony Broke]

I recently put a Green Mountain .45 barrel on a TC Hawken and added peep sights. With the first load I tried in it, it was one of the most accurate barrels I have ever owned. The last match I shot it in, out of four differrent targets, I shot four possibles !! Nothing needed to be done to the barrel....

 

[Eric Krewson]

I just put a Green Mountain ,54 drop in in one of my TCs, it had a sharp crown and blew the patches. I recut the crown and gave it 100 strokes with an oily gray scotch bright pad patch, I haven't shot it yet but suspect the days of the gun blowing the patches are over.

I have done this to other barrels in the past and had great results.

 

[Loyalist Dave]

I acquired a 32 inch green mountain barrel .50 caliber 1:66 unfired. I heard from a fellow shooter/co worker that I'll have to shoot about 100 patched round balls to break in the barrel because of how sharp and new the rifling is inside the bore. Just curious to other people's thoughts on this subject.

Green Mountain barrels in the past, were well made but did not get the polishing that the high cost Rice barrels receive. I write "in the past" as they stopped for a while on BP barrels, and made barrels for the US Government. I've not heard if the barrels have cutting patch problems since the company returned to making BP barrels. So there is a possibility of cutting patches, and you should inspect your patches when shooting to be sure. On the other hand I've had Pedersoli barrels cut patches too.

LD

 

[hunter thompson]

MY father built rifles in the 70s and got barrels from dixie..then i re he had to lead lap them with a oversize ball pushing it up n down to smooth the inside.That 45 was for head shots on squirrls and is very accurate.

 

[Nobade]

I recently did this with my Bob Hoyt rebore. It was cutting patches and shooting poorly at first but I ran an entire pound of powder through it one afternoon and at the end it loaded easily, patches looked good, and was shooting very tight groups.

 

[Bad Karma]

I recently did this with my Bob Hoyt rebore. It was cutting patches and shooting poorly at first but I ran an entire pound of powder through it one afternoon and at the end it loaded easily, patches looked good, and was shooting very tight groups.

I’ve used the Shaver break in method a few times (steel wool tightl fitted and about 100 strokes.) I’ve fire lapped barrels and also just shot the thing a hundred times with tight patches. My paper patch rifles smooth out very nicely in just a few dozen shots. All work just fine.

 

[Thekingd93]

I have a pound of pyrodex that I don't use, suppose I could use that stuff instead of my good Swiss and Goex powder to break it in.

 

[45man]

I would not bother too much as Green Mountain makes quality barrels. I would just go shoot.

 

[hanshi]

Sharp and burred bores are not as common as we are sometimes lead to think. The only thing I do initially to a new barrel is to polish the crown well so muzzle entry is smooth. Most torn patches are torn at the muzzle and not by the rifling when the prb is being seated. Shoot it with your Pyrodex and save your Swiss if you like. But you can also start load development with your Swiss and not worry.

 

[Thekingd93]

Sharp and burred bores are not as common as we are sometimes lead to think. The only thing I do initially to a new barrel is to polish the crown well so muzzle entry is smooth. Most torn patches are torn at the muzzle and not by the rifling when the prb is being seated. Shoot it with your Pyrodex and save your Swiss if you like. But you can also start load development with your Swiss and not worry.

I recently watched a video with Idaho Lewis on YouTube demonstrating the benefits of an over powder patch that helps protect the main patch. Possibly would be beneficial in the new barrel

 

[M. De Land]

Sharp and burred bores are not as common as we are sometimes lead to think. The only thing I do initially to a new barrel is to polish the crown well so muzzle entry is smooth. Most torn patches are torn at the muzzle and not by the rifling when the prb is being seated. Shoot it with your Pyrodex and save your Swiss if you like. But you can also start load development with your Swiss and not worry.

I completely agree that most patch tearing is from the crown at loading in a new barrel.

 

[Nobade]

I completely agree that most patch tearing is from the crown at loading in a new barrel.

In my case I could feel two very tight spots in the barrel. I really had to whack the rod at first to get the ball past them, but as I shot they got easier until it went down with equal force all the way and in one smooth motion. The roughness going away also correlated to the groups getting tighter. I had already done a nice polished crown on it when I got it back from Bob, so it wasn't that.

 

[M. De Land]

In my case I could feel two very tight spots in the barrel. I really had to whack the rod at first to get the ball past them, but as I shot they got easier until it went down with equal force all the way and in one smooth motion. The roughness going away also correlated to the groups getting tighter. I had already done a nice polished crown on it when I got it back from Bob, so it wasn't that.

Well , what is happening with a new crown and particularly with a high polished crown is that the corner of the crown into the end of the lands and bottom of the grooves is often made more acute (sharper) at the transition. Until this edge is dulled a bit by use or mechanically lapped to a chamfer it puts the most stress on the patch material of any part of the loading process .
If you have a tight spot in the bore it can be roughness of reaming or rifling but often times is an actual constriction of a few ten thousands that may need a hand lap job to remove. This is easily checked with an appropriately sized plug gauge.

 

[Eric Krewson]

I use a bush fix crown cutter on sharp crowns, it works well but wears after a couple of crowns and looses its angle. These are maple and I need to make one out of hickory or osage for toughness. I rotate the drill position 45 degrees every 5 seconds and only use the weight of the drill for pressure.