Green Mountain barrel problem?

[BrianL]

I am in need of some help, information, advice, maybe some calming words.

There have been several threads lately about GM barrels and I have 4 in 54 and 32 cal. I just ordered and received one in 40 cal,direct from the factory.
I bought this drop in Hawken barrel with the intent to use it primarily for PBR but I also have followed with interest the threads about Oldnamvet' REAL bullets and actually own one of the molds.

I tried the barrel today with both the PRB and the REAL bullets. My bench was set up at 50 yds so I hung a target at that range and after cleaning , shot 5 shots with 50 gr 3f. I went up to check the target and had 4 shots in about 3 1/2 inches and the other one missing. I do not expect tight groups with the factory sights but also do not expect misses. Walking back I looked for my patches and found only the twisted remains of two of them, shredded.This is .017 denim. The barrel seemed tight for the first 18 inches or so, then considerably looser. After shooting about twenty balls, I cleaned it up good and tried the REALs. They went in thumb tight and I could feel them engaging the rifling again for the first 18" or so. Then it eased and at about 20" dropped with the ramrod weight alone :shocked2:

I am not sure what to think here. Did I get a lemon?

 

[necchi]

FWIW, I don't think you got a lemon.
It's just the nature of barrels.
I have 2 GM barrels, one as a drop in that didn't fit until I made it fit, and both required a significant break in period.

After I had 150-200 shot's down the bore and learning what they like and don't like I have two tack-driving barrels.

I've seen and heard of guy's talk of "out of box" accuracy with new GM barrels, but you never see them walking to the trophy table, they're always too busy to shoot, never shoot with others or some other story.

Some folks like advanced scrubbing or polishing methods, using some kind of abrasive or another.
Ijust do what's called "shoot'm in", my break in period is what I said 150-200 shot's and you'll be suprised how nice they can be.

The first biggest deal is cleaning, they pack a heavy shipping/storage grease in those things, if that's not all cleaned out till a "white patch comes out white" there's trouble from the get go,,

 

[BrianL]

Just finished cleaning it up and noticed that even the cleaning patches are a little cut up. I was only able to find about half of the fired patches and they ranged from little balls of material to long twisted shreds. What would this indicate?

The barrel seems tightest at the first 3-4 inches.

In regard to the break in, would accuracy be horrendous until it settled in? It did not keep all five on the paper once in four groups.
To be fair, my eyes are iffy and I generally use a receiver sight.
I will switch out the stock for one of the tang sighted ones tomorrow.

I guess that the other 4 barrels kind of spoiled mme as they did shoot very well out of the box.
What are your thoughts about the REAL just dropping after getting down 2/3rds of the way down?.

My immediate concern is whether GM will take a return if after 200 shots it is still not doing well :idunno:

I did clean the barrel before shooting but it may not have ended up white patch clean. When you say trouble from the get go do you mean just poor accuracy?

 

[Mad Professor]

Besides what has been said about breakin until the lands are not sharp.....

Check the screws on the rib. I got a GM barrel that came with a loose rib/ 1 screw missing, that I did not notice. I could not figure out the flyers until I tightened things up.

Also check the rear sight and that there is no play at tang or staple

 

[necchi]

Well then I'd suggest you contact GM about a warrenty issue.
If you have had experiance with 3 other GM barrles and this one has issues different than the others it must be a bad barrel.
Your first recourse should be to protect your investment. I wouldn't want to be responsible for any loss you might have.

 

[BrianL]

Well then I'd suggest you contact GM about a warrenty issue.
If you have had experiance with 3 other GM barrles and this one has issues different than the others it must be a bad barrel.
I wouldn't want to be responsible for any loss you might have.

Necchi,
I appreciate your help and was quite glad to hear you opinion that it was probably just a matter of 'shooting it in' especially when it has been your personal experience. I then expanded my questions for more of your insight as to what to expect. I did not insinuate that the other three barrels were anything more than that the luck of the draw had been favorable.

Seriously,
Thanks again

 

[necchi]

I had one issue with a GM drop in,
It had the "Helicoil" repair made to it that was a judgment call from GM Management.
Word was the repair was just fine , but those that wanted a breech plug without the Helicoil could get the repair done without cost, they even paid shipping.
It took 14wks to get my barrel back, here in MN that was an entire shooting season.

And while that and the other GM barrel I have didn't get real nice groups until break in, neither was really that bad, they where more like 2" groups at 50 instead of the one hole they get now.

Tuff part is going to be talking to the right person at GM,,

 

[BrianL]

Besides what has been said about breakin until the lands are not sharp.....

Check the screws on the rib. I got a GM barrel that came with a loose rib/ 1 screw missing, that I did not notice. I could not figure out the flyers until I tightened things up.

Also check the rear sight and that there is no play at tang or staple

I checked the sight and rib this morning and every thing is tight there. I did notice that there is some resistance/springiness as the barrel seats into the stock. I am assuming that this is caused by an excess of metal at the top of the hook. I have posted that question at the gunsmithing bench as well in hopes of finding the best method to approach this if it can affect accuracy.
Thanks

 

[CoyoteJoe]

I usually find it quicker and easier to fix things myself than to ship it off for warranty work but in this case I'd say "send it back". I've had barrels with loose and tight spots and they never shoot really well. I have hand lapped tight spots out of a barrel or two but it is a heck of a lot of hard, dirty work. Send it back.

 

[necchi]

I usually find it quicker and easier to fix things myself than to ship it off for warranty work but in this case I'd say "send it back". I've had barrels with loose and tight spots and they never shoot really well.

Sage advice.
I haven't had that trouble, if I can do it myself I prefer too,
But that issue of tight/loose spots is what lends me to say it's would be beyond my ability to fix or a break in issue.

 

[Dphar]

I am in need of some help, information, advice, maybe some calming words.

There have been several threads lately about GM barrels and I have 4 in 54 and 32 cal. I just ordered and received one in 40 cal,direct from the factory.
I bought this drop in Hawken barrel with the intent to use it primarily for PBR but I also have followed with interest the threads about Oldnamvet' REAL bullets and actually own one of the molds.

I tried the barrel today with both the PRB and the REAL bullets. My bench was set up at 50 yds so I hung a target at that range and after cleaning , shot 5 shots with 50 gr 3f. I went up to check the target and had 4 shots in about 3 1/2 inches and the other one missing. I do not expect tight groups with the factory sights but also do not expect misses. Walking back I looked for my patches and found only the twisted remains of two of them, shredded.This is .017 denim. The barrel seemed tight for the first 18 inches or so, then considerably looser. After shooting about twenty balls, I cleaned it up good and tried the REALs. They went in thumb tight and I could feel them engaging the rifling again for the first 18" or so. Then it eased and at about 20" dropped with the ramrod weight alone :shocked2:

I am not sure what to think here. Did I get a lemon?

Once sized to the bore a lead bullet will have no significant friction. This is why they are a risk for sliding away from the powder and forming a bore obstruction.
I would shoot a 395 ball and 40-70 grains of powder with a patch that measures .018 or so with some compression. I.E. A micrometer turned down with a somewhat more force than is provided with the slip clutch. The heavily sized (stiff) blue stripe ticking from Jo-Ann fabrics will be about right or NEW denim about 9-10 ounce weight. Used denim (old jeans) is not uniform. Some heavy drill may work but its usually too thin.
Try different patch lubes and patches. Did you retrieve and patches downrange? Were they whole and seemingly ready to relube and shoot? If not you have a ball fit/patch/lube problem.

Some barrels will shoot very well with spit only.
Buy some PURE Neatsfoot Oil apply to patches then squeeze pretty dry and try them both squeezed dry(a friend uses a vise to dry the patch) or pretty wet and see if this works.
For best accuracy if using anything but a water based lube wipe the bore every shot, one damp (uniformly wet but NOT dripping, too much water will put too much water in the breech) patch both sides, dry patch both sides. Using a fairly loose jag not a tight one.
The barrel will probably shoot through the same home with no wind and the right powder/patch/ball/lube and uniform wiping.
If its blowing patches the crown might be the problem. Seat a ball using a lubed strip of patching then pull it back out and check for damage. If it tears off leaving the ball you have a real problem either with the material being too weak or the crown cutting the patch.
If the patch shows fraying or cuts then some polishing is needed. This can be done by hand with 400 grit paper by carefully pressing the paper against the crown with a thumb or finger tip and rotating changing position to polish uniformly.
A patch with a wad of 0000 steel wool a can be run up and down the bore 20-40 strokes if you think it might have some sharp edges down the bore. Tight fit is better. GM barrels probably don't need this but who knows.

Check out http://www.blackpowderrifleaccuracy.com/
This REALLY works. But most think its too much trouble, its not if its a serious rifle match. I get water soluble oil from our local CarQuest auto parts/machine shop.

Dan

 

[BrianL]

I just cast a bunch of balls. Unfortunately it is a .390 mold. I thought that I had ordered the .395
I found some of my thickest pillow ticking .022/.023, and a big bag of cleaning patches. Off to the bench.

I am hoping that this is what Dan has mentioned in that the sharp lands are mostly close to the muzzle and have engraved the REAL bullets to the point that they have no more resistance to offer. I have never used conicals of any design so I was not sure what to expect. Thanks

 

[Dphar]

PS:
If its tight at the muzzle and looser to the breech its called a choke. A common interior in original barrels.
MANY, MANY top grade barrels back in the day, including the original Hawken barrels, were choked. It was basically standard on target MLs back in the day. It eases loading and improves accuracy.
So shoot the barrel first and wring it out before declaring it faulty.
A VERY slight enlargement will cause a sized bullet to drop free. This should not be a problem and might be a benefit if it does not get tight again at the breech. Loose at the breech to tight toward the muzzle is OK. Tight, loose, tight is not so good.
Even breech loading BP arms will shoot well to best with a choke. The Springfield Rifle Musket, for example had deeper grooves at the breech than at the muzzle. The rifling gets progressively shallower from breech to muzzle. A form of choking.

Dan

 

[hanshi]

I've found this slight "choke" on most of my rifle barrels and my smoothbore as well.

 

[Dphar]

Here is a short passage from John Baird's "Hawken Rifles, The Mountainman's Choice" Pg 42 in which he and T.K. Dawson examined the bore and then test fired a "Hoffman & Campbell" Hawken rifle:
"...Of 50 caliber, the bore is a slight taper from the breech to a point 9 1/2 inches from the muzzle. Hear a choke is apparent for about 8", then from there to the muzzle, a slight flaring is seen. Measuring approximately .0005", about 1/4" from the of the barrel, this flare suddenly increases and additional .002..."

The way the barrel is choked is very common.
Dan

 

[BrianL]

Would this allow gases to pass the ball/patch in the looser portion before hitting the choke?

I am taking a quick break. After 48 balls downrange so far today with swabbing between shots. There appears to be a bit less fouling as I go along. The last two groups actually show promise, I think that with the tighter ball, this will probably be better.

Seeing is believing in one respect. :bow:
I shot 5 shots dirty and saw the first two patches hit the ground. Two others had a perfectly round hole ripped out of the center and the 5th was shredded :shocked2: The group was the worst of all.

Most of the patches prior to this looked reuseable

 

[aeatwood]

I would try bumping the charge a bit too. My GM barrels like full service charges. Some of them shoot well w/ reduced loads too, but since 99% of my shooting is geared to hunting prep, only my .32 barrel sees much in the way of light loads. BTW, a .32 on a 15/16" barrel is a bit...weighty.

Alan

 

[necchi]

FWIW, both my GM's shoot the large for caliber ball better,
.535 --.395

 

[Dphar]

Would this allow gases to pass the ball/patch in the looser portion before hitting the choke?

Like I said a lot of barrels were choked.
The barrel cited above shot 20 shots with 4 different powder charges (70-90-110-130 gr) making a 50 yard group 2" wide by 2 1/2" tall.
Blow patches can be almost anything. I bought a couple of yard of ticking 20 odd years ago that would blow a patch ever 5-6 shots. Something the rifle has never repeated.
I have a GM that will blow patches using the Schoultz method unless I put a patch over the powder before loading the patched ball. If a slicker lube is used it does not do this with all other variables the same.
My McLemore barrel shooting a heavier charge of powder does not damage Schoultz method patches.
It requires testing. I was going to do some shooting today to test some denim I bought but the wind is howling....


Dan

 

[BrianL]

An update on this barrel.

You were all right! :bow:

After 180 clean -fire-clean rounds the group went from only 11 of 15 shots on the paper at 50 yds to a 1.600 c to c group at end of day today. I think that the early morning raid at Frank's Bargain Fabrics to grab som .027" denim may have helped a lot.
Now to sight it in............

Thanks to all of you! :thumbsup: