barrel advantage?

[horseman]

 I was looking at the difference between Green Mtn. and Colerain barrels.  The first had eight grooves that were .010 to .012" deep and the latter had six grooves hat were .016" deep.   What, if any advantage would one have over the other?  Thank you for your time and help.

[JCKelly]

The one is made of 1144Mod, used in lower price modern shotgun barrels.

The other is 12L14 meant for maximum machining speeds, such as hardware screws. Try twisting the head off of one of them.

[bob in the woods]

The Colerain barrel has round bottomed 16 thou deep rifling. Thicker patched required. Very easy to clean, and load in the field. I prefer this type of barrel for hunting.
The Green Mountain barrel  I have on my percussion under hammer target rifle has square bottom rifling , depth as you describe. It is extremely accurate and loads easily, although the square corners of the grooves can require a bit more effort to clean. Either one of these barrels will do a great job for you. They are great shooters with the right load. Take your pick.

[flehto]

Don't know why modern MLing bbls have grooves .016 deep seeing w/ this depth  it's quite difficult for the patch to seal the bore. A bbl w/ .010-.012 deep rifling will  still grip the PRB and the patch has a much better chance of sealing the bore.  Perhaps .016 deep radius groove rifling would allow better sealing of the bore, but still think the depth is excessive.

Radius groove rifling allows easier cleaning of the grooves because of the lack of groove  sharp corners. Some say that square groove rifling is more accurate than radius groove rifling,.....don't know of any tests that confirm that.

For the pressures generated w/ BP, 12L14 has sufficed...haven't heard of a whole lot of bbls failing w/ this steel due to norrmal shooting. Sure there are steels that are "stronger", but are they needed for BP pressures?.....Fred

[Bob Roller]

Don't know why modern MLing bbls have grooves .016 deep seeing w/ this depth  it's quite difficult for the patch to seal the bore. A bbl w/ .010-.012 deep rifling will  still grip the PRB and the patch has a much better chance of sealing the bore.  Perhaps .016 deep radius groove rifling would allow better sealing of the bore, but still think the depth is excessive.

Radius groove rifling allows easier cleaning of the grooves because of the lack of groove  sharp corners. Some say that square groove rifling is more accurate than radius groove rifling,.....don't know of any tests that confirm that.

For the pressures generated w/ BP, 12L14 has sufficed...haven't heard of a whole lot of bbls failing w/ this steel due to norrmal shooting. Sure there are steels that are "stronger", but are they needed for BP pressures?.....Fred

I feel better with "stronger" materials for gun barrels. I see 7/8" barrels in 50 caliber made from uncertified steels and wonder why anyone would want such a thing. A lot of things have sufficed in the world of muzzle loading rifles but that doesn't mean they have to be accepted.

Bob Roller

[smylee grouch]

Maybe some of the barrel makers could chime in as to why the groves in a radius grove barrel are so deep compared to the square grove types. I viewed ancouple of original rifles at The Mineapolis Insitute  of Art that had round grove cuts and they didn't appear to be near that deep and were more of an U shape than the current trend.

[JCKelly]

Stronger?

Strong is good to keep the barrel from bulging. Ductile is necessary to keep the thing from shattering when something goes wrong. 

Just for fun, here is quote from an 1888 report of the Birmingham Proof House:

"The endurance of a barrel appears to depend upon a moderately high elastic limit (which prevents bulging) and a fair margin between the elastic limit and the breaking strain (which prevents bursting). If the composition of the metal and the method of manufacture are such as to yield a low elastic limit, the barrel is too soft and bulges easily; while, if the elastic limit be unduly raised in proportion to the ultimate tenacity, the metal is deficient in ductility, and, being thus brittle, the barrel bursts"

The original paper is from Experts on Guns and Shooting, p 264, Longon, 1900, reprinted by The Buckskin Press, Big Timber Montana, 1981.

[Acer Saccharum]

I don't like really deep grooves, as it can be a challenge to find a patch/ball combination that won't blow gas through the grooves.

[David R. Pennington]

I lean toward square bottom grooves personally. I have a .50 and a .40 both Green Mtn. and they both shoot better than I can hold. I just pulled the breechplug on the .40 after shooting a match with it Saturday. First time I had pulled it since I built in in 08. I always clean in the field with just water and oil with bear oil. Bore cleaned up mirror bright. I have a radius groove .62 that shoots pretty good but I get better groups at 100 yds. with the .40 and .50, but that might be me reacting to the slightly higher recoil of the bigger bore.

[D. Taylor Sapergia]

Today, I shot the percussion Hawken rifle I just finished.  I sighted it first at 25 yds from a bench rest, and since I had an 80 gr. charger, that's what I used.  I shot a ragged hole for five shots, and was satisfied.  Until I tried it at 50 yards.  Lousy!!

So I used the measure I had tied to the pouch I have designated for my own .62 cal Hawken which throws 127 gr.  I was using GOEX 2F Cartridge BP.  At 50 yds. I shot a group of about 1 1/2" and felt if I had spent some more time, I could have improved upon that.

The lesson here is that the big bored slow twist barrels like a decent charge.  Recoil was not unpleasant in this 9 pound rifle.  This barrel is a Rice with ;round bottomed grooves.  I used a .613" LYman poured pure lead ball and .022" denim patch with spit.  With the short starter, it loaded very easily.  I could have re-used the patches.

[Nordnecker]

I recently finished a .40 cal rifle with round bottom rifling. I've only shot it at 25 yards. The patch I use in my other .40 (with square rifling) felt really loose in this barrel. I ended up using some flannel from an old shirt. It felt too loose as well, but some other ticking I had was too thick and I couldn't get it started. Oddly, I couldn't find the patches after shooting the first 4 shots. I found 1 and it wasn't burnt but it had 2 little holes in it. I quit after 5 shots because I figured my results were pretty inconclusive due to the patching. The group was about 1 inch. The barrel cleaned up very easily. It only took about 6 or 7 patches.

[smylee grouch]

Nordecker, you might want to check the crown on that 40 and give it a polishing. The tight load starting combo might be ok then.

[Bob Roller]

Today, I shot the percussion Hawken rifle I just finished.  I sighted it first at 25 yds from a bench rest, and since I had an 80 gr. charger, that's what I used.  I shot a ragged hole for five shots, and was satisfied.  Until I tried it at 50 yards.  Lousy!!

So I used the measure I had tied to the pouch I have designated for my own .62 cal Hawken which throws 127 gr.  I was using GOEX 2F Cartridge BP.  At 50 yds. I shot a group of about 1 1/2" and felt if I had spent some more time, I could have improved upon that.

The lesson here is that the big bored slow twist barrels like a decent charge.  Recoil was not unpleasant in this 9 pound rifle.  This barrel is a Rice with ;round bottomed grooves.  I used a .613" LYman poured pure lead ball and .022" denim patch with spit.  With the short starter, it loaded very easily.  I could have re-used the patches.

[Bob Roller]

Today, I shot the percussion Hawken rifle I just finished.  I sighted it first at 25 yds from a bench rest, and since I had an 80 gr. charger, that's what I used.  I shot a ragged hole for five shots, and was satisfied.  Until I tried it at 50 yards.  Lousy!!

So I used the measure I had tied to the pouch I have designated for my own .62 cal Hawken which throws 127 gr.  I was using GOEX 2F Cartridge BP.  At 50 yds. I shot a group of about 1 1/2" and felt if I had spent some more time, I could have improved upon that.

The lesson here is that the big bored slow twist barrels like a decent charge.  Recoil was not unpleasant in this 9 pound rifle.  This barrel is a Rice with ;round bottomed grooves.  I used a .613" LYman poured pure lead ball and .022" denim patch with spit.  With the short starter, it loaded very easily.  I could have re-used the patches.

My computer just had a spasm when I started to type. I have made only one Hawken type using a solid patent breech Bill Large Barrel that was 34" long x 1/18" ATF and 54 caliber. I used a .535 pure lead ball with 120 grains of DuPont 3fg.The patch was WW2 military surplus. I bought what was represented as 100,000 in a BIG bag from Wes Kindig. This gun was finished,complete with real brass tacks on Thanksgiving Day in 1967. That was 49 years ago.I kept this load as the standard for it and shot a 5 leaf clover at 100 yards on Christmas day of that year.The sights were of the type common to those rifles back in the "day".The patch was "Lubed" with a concentrate called Black Solve that looked like anti freeze when mixed with water. The little bottle made about a half gallon as I recall and it worked. I saturated the patches with it and put about 50 of the between two flat boards and mashed the with a moderate pressure so they were very damp but not dripping the next morning.
That is an old Harry Pope trick for patches used for wiping between shots in a 32-40 Ballard.

Bob Roller

[WadePatton]

I was looking at the difference between Green Mtn. and Colerain barrels.  The first had eight grooves that were .010 to .012" deep and the latter had six grooves hat were .016" deep.   What, if any advantage would one have over the other?  Thank you for your time and help.

off point somewhat:

Problem for me is I don't know the barrelmaker's name at either place.  I like knowing the man behind the 'chinery, few chances to do that today.  Take advantage.

Everyone has their preferences for their reasons.  There's mine. 

[bob in the woods]

I just dug out my copy of Muzzleloader Magazine, Sept/Oct 2009    "Round grove vs Square groove" by Fred Stutzenburger and Brian Turpin . Very interesting , controlled test between the two styles. In this case the round bottom rifling ended up with a group of 1.7 inches while the square bottom rifled barrel shot a 2 in group.
The round bottom rifling showed a slight edge over the entire range of powder charges tested. [ 50 yards ]

[Daryl]

Much depends on the barrels used, the experience and methodology of the testers. We dont know if those were the best loads in each rifle, or if they picked a given load and tried it in each and noted the average accuracy.

Here's a 5 shot group at 50yards, with square rifling when testing weird, uncommon loads.



Here's a 10 shot group at 50yards with the same rifle using a proper sized ball and proper patches that actually shoot well in that rifle.

Both groups are as good or better than the guns used in the 'test'. My 'old' .40 and current .45 do even better with select loads, making "down to" 1/2" groups at 50yards.

[bob in the woods]

Daryl, you are absolutely correct.   But the article is "interesting"       I have rarely seen a barrel from a North American maker not be capable of shooting into an inch or less at 50 yards with the right load. 

[JCurtiss]

Stronger?

Strong is good to keep the barrel from bulging. Ductile is necessary to keep the thing from shattering when something goes wrong. 

Just for fun, here is quote from an 1888 report of the Birmingham Proof House:

"The endurance of a barrel appears to depend upon a moderately high elastic limit (which prevents bulging) and a fair margin between the elastic limit and the breaking strain (which prevents bursting). If the composition of the metal and the method of manufacture are such as to yield a low elastic limit, the barrel is too soft and bulges easily; while, if the elastic limit be unduly raised in proportion to the ultimate tenacity, the metal is deficient in ductility, and, being thus brittle, the barrel bursts"

The original paper is from Experts on Guns and Shooting, p 264, Longon, 1900, reprinted by The Buckskin Press, Big Timber Montana, 1981.

Interesting, thanks for posting. 

Wow, materials have certainly advanced dramatically since the 1800s.  As you know it's not uncommon to find material with a minimum yield strength of 80,000 psi to be ductile too.

Barrels today appear to be made from mild steel, 36,000 psi min yield, which is certainly ductile.  Can you confirm this supposition?

[Gaeckle]

I don't like really deep grooves, as it can be a challenge to find a patch/ball combination that won't blow gas through the grooves.

Absolutely!