Colerain gain twist round bottom barrels

[jtkerk]

Was just wondering what are some of your findings on shooting these barrels? I have one in a 54 caliber gain twist round bottom rifling and was wondering what other people’s experiences when shooting these barrels were. Thought might provoke some interesting discussions.

 

[M. De Land]

Was just wondering what are some of your findings on shooting these barrels? I have one in a 54 caliber gain twist round bottom rifling and was wondering what other people’s experiences when shooting these barrels were. Thought might provoke some interesting discussions.

I have always wanted to experiment with a gain twist and think it makes sense in a patched ball barrel. They also seem to work in a bullet shooting barrel but have never been proven to be any more accurate than a well cut even twist pattern.
The reason it makes sense to me in patched ball use is because of the short contact area to the rifling of a patched ball where as in an elongated bullet the nose is always trying to out spin the base for a certain amount of stripping.
The only advantage I can think of for this occurring is that the progressive resistance may neutralize barrel movement by harmonic dampening.

 

[Mattox Forge]

The only advantage is the ability of obtain higher muzzle velocity for a given twist than you could with a straight twist barrel. What is the final twist on your barrel?

A faster twist theoretically gives you better precision, i.e. smaller groups. However, the high initial torque imparted on the projectile in a straight fast twist barrel limits the muzzle velocity you can obtain with patched lead projectiles, causing lower powder charges and consequently lower muzzle velocities. Lower muzzle velocities are not inherently inaccurate if you know the range accurately. But in field use where targets are not at known ranges, range to target errors and subsequent sighting errors cause innacuracy. Additionally the terminal effects are not as good because of lower muzzle velocities.

For straight up known distance target shooting I doubt that there will be a percieved advantage with a gain twist barrel.

For practical hunting, there is a theoretical advantage with the ability to shoot a given projectile with more precision because of the higher spin rate and with better accuracy due to the ability to get higher muzzle velocities and to realize a slightly flatter trajectory and also to have higher velocity at the target for better terminal effects.

Mike

 

[bldtrailer]

ok not their barrel but a Hoyt gain twist 54

this one is a gain twist hoyt in 50 dead on at 50yrds a little high at 75 dead one low

at 100 , my other Hoyts 1-56 are on at 50 high at 75 3-4 inches low at 100 with the same load 3f swiss 80 grns 490 ball .20 denim patch tallow lube

FLATTER SHOOTING than the same load in a constant twist barrel

 

[bldtrailer]

here's groups with reg twist barrels
getz .50

green mountain .50 1-70

hoyt .50 1-56

so any good barrel can shoot tight groups if you work up a good load

 

[Bad Karma]

Mr Hoyt says gain twist will give you a 200 fps advantage… he does know his barrels.

 

[jtkerk]

The only advantage is the ability of obtain higher muzzle velocity for a given twist than you could with a straight twist barrel. What is the final twist on your barrel?

A faster twist theoretically gives you better precision, i.e. smaller groups. However, the high initial torque imparted on the projectile in a straight fast twist barrel limits the muzzle velocity you can obtain with patched lead projectiles, causing lower powder charges and consequently lower muzzle velocities. Lower muzzle velocities are not inherently inaccurate if you know the range accurately. But in field use where targets are not at known ranges, range to target errors and subsequent sighting errors cause innacuracy. Additionally the terminal effects are not as good because of lower muzzle velocities.

For straight up known distance target shooting I doubt that there will be a percieved advantage with a gain twist barrel.

For practical hunting, there is a theoretical advantage with the ability to shoot a given projectile with more precision because of the higher spin rate and with better accuracy due to the ability to get higher muzzle velocities and to realize a slightly flatter trajectory and also to have higher velocity at the target for better terminal effects.

Mike

1 in 70 I believe

 

[jtkerk]

ok not their barrel but a Hoyt gain twist 54View attachment 300977View attachment 300978View attachment 300981this one is a gain twist hoyt in 50 dead on at 50yrds a little high at 75 dead one low View attachment 300983 at 100 , my other Hoyts 1-56 are on at 50 high at 75 3-4 inches low at 100 with the same load 3f swiss 80 grns 490 ball .20 denim patch tallow lubeView attachment 300982FLATTER SHOOTING than the same load in a constant twist barrel

Wow some really cool and good information

 

[jtkerk]

ok not their barrel but a Hoyt gain twist 54View attachment 300977View attachment 300978View attachment 300981this one is a gain twist hoyt in 50 dead on at 50yrds a little high at 75 dead one low View attachment 300983 at 100 , my other Hoyts 1-56 are on at 50 high at 75 3-4 inches low at 100 with the same load 3f swiss 80 grns 490 ball .20 denim patch tallow lubeView attachment 300982FLATTER SHOOTING than the same load in a constant twist barrel

I wish i could shoot that precise with open sights my older eyes aren’t what they used to be

 

[jtkerk]

here's groups with reg twist barrels
getz .50
View attachment 300985View attachment 300986green mountain .50 1-70View attachment 300987View attachment 300988hoyt .50 1-56View attachment 300989
so any good barrel can shoot tight groups if you work up a good load

here's groups with reg twist barrels
getz .50
View attachment 300985View attachment 300986green mountain .50 1-70View attachment 300987View attachment 300988hoyt .50 1-56View attachment 300989
so any good barrel can shoot tight groups if you work up a good load

Nice shooting. I’d love to see close up photos of your peep sight

 

[M. De Land]

Wow some really cool and good information

One of the quirks of gain twist single point rifling is that the lands become narrower and grooves wider as the pitch increases. This is because the rifling head increases it's cross section as the helix angle is increased thus making it shave out a bit wider groove.
Think of the rifling tooth being in a square or rectangular vertical profile and then turn it a bit toward a diamond shape which will be wider than the square or rectangle it starts as. Same thing happens when the pitch is increase up bore toward the muzzle.
Gain twist also cannot be lead slug lapped as can even twist but it can be muti- disked leather lapped for choking or tapering purposes.
There has never been any solid proof that gain twist is more accurate than even twist and it has been tested for over a century by some of the finest barrel makers ever born.
It is far more labor intensive to produce well and as stated cannot be lead slug lapped for evening the groove depth as can even twist rifling.

 

[bldtrailer]

Just a note I only use the peep sights when working up the load (I want to find what the rifle likes) only group in the above posting shot with a peep was the green mtn all the rest are open sights bench rested

 

[bldtrailer]

As far as lapping a barrel I do what Mr Dixon told me years ago brass brush wrapped with 0000 steel wool and light oil 50-100 strokes, clean and repeat.
It has shrunk my groups in every barrel I've lapped.

If your barrel cuts your patch lap it

 

[jtkerk]

One of the quirks of gain twist single point rifling is that the lands become narrower and grooves wider as the pitch increases. This is because the rifling head increases it's cross section as the helix angle is increased thus making it shave out a bit wider groove.
Think of the rifling tooth being in a square or rectangular vertical profile and then turn it a bit toward a diamond shape which will be wider than the square or rectangle it starts as. Same thing happens when the pitch is increase up bore toward the muzzle.
Gain twist also cannot be lead slug lapped as can even twist but it can be muti- disked leather lapped for choking or tapering purposes.
There has never been any solid proof that gain twist is more accurate than even twist and it has been tested for over a century by some of the finest barrel makers ever born.
It is far more labor intensive to produce well and as stated cannot be lead slug lapped for evening the groove depth as can even twist rifling.

Some very interesting facts. I also heard in theory that gain twist with round bottom rifling cleans easier. Not sure if I can confirm this due to not having barrel that long but seems to clean up easier. Anyone else have some thoughts?

 

[jtkerk]

Thanks for the photos. I was thinking of doing the same thing