Is 357 velocity faster when leaving 16 inch Trapper or 20 inch carbine lever rifles?

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valleyforge.1777

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Is 357 velocity faster when leaving a 16 inch Trapper or 20 inch carbine lever rifles?

Assuming one has both a 16 inch Trapper Winchester model 94 in 357 and a 20 inch carbine Winchester model 94 in 357, firing the same ammo, which one would have the higher velocity? I don't have a chrono to find out. Does anyone know?

"Logic" says that the longer barrel will produce higher velocity, but somewhere along the way of life I think I recall reading that the longer barrel of the 20 inch carbine actually slows the bullet down before it exits the muzzle end, compared to the 16 inch Trapper. Does anyone know if that's true?
 
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I'm pretty certain the longer barrel will be faster, but not by a whole lot. It shouldn't be the deciding factor for which one to buy.
 
These are 357 Model 94AE's with scopes.

I am really trying to decide which one to sight in (scope) at 100 yards for 357 Mag and which one to keep scope sighted in at 50 yards for 38's.

I figure that the one with the higher velocity with 357 will get sighted in for 100 yards and the slower one will get sighted in for 38's at 50 yards.

Not trying to make it a trick question, because it seems obvious that the 20 inch barrel should yield a higher velocity than the 16, but I have this nagging feeling that somewhere I read that for 357 it actually starts slowing down by the time it exits the 20 inch barrel. But then again, maybe what I read was referring to the 24 inch rifle barrel rather than the 20 inch carbine barrel. I don't know! I can't remember where or what I read. Or, when I read it!

Anyway, if anyone has a thought, please chime in.

[Ps. A scope at 50 yards? Yes. Eyesight issues.]
 
You don't need a chronograph to see which will have better ballistics.

Since you have both, take them to the range. Set up a target at 50 yards, 100 and 150 yards. Sight in both to the same point of impact at 50. Shoot both at the 100 and 150 yard targets. The one with the least drop at both 100 and 150 is the better set up for longer range. Provided that group size is good enough for your purpose.

Several factors determine the trajectory of a bullet. Velocity is a big factor but scope hight from center of the bore can have a big part as well. The only way to know for sure is to shoot both and see.
 
Depends upon the burn rate of the powder, I would think.

A very fast powder would actually generate a slower velocity (at safe pressure) in the longer barrel- you'd get to max pressure before you got top velocity.

Longer barrels favor slower powders, generally.
 
Depends on the Powder.

A light charge of fast burning powder will reach peak velocity sooner and begin to drop pressures below the point of further gains; so that 16" barrel may very well shoot faster with such a load. However, a heavy charge of AA-9, IMR-4227, H-110 and the like will make the longer barrel shoot substantially faster.
 
You can actually see here that the 357 starts slowing down after 16 inches of barrel length.
Click to expand...

I checked out the link and found it very interesting that the bullet slows down with a 17' barrel and then speeds back up one inch later with the 18' barrel . :confused: Almost every ammo tested did this . does anybody know why ?
 
I checked out the link and found it very interesting that the bullet slows down with a 17' barrel and then speeds back up one inch later with the 18' barrel . Almost every ammo tested did this . does anybody know why ?
Click to expand...

We're pretty sure that there must have been a problem with the barrel chop/recrowning on that 17" test sequence. But we don't fudge the data, so showed it errors and all.

It might help to also look at our "Cylinder Gap" test results, which include a full second test sequence of chop tests. It's not a complete repeat using the same ammo as the first sequence, but there's a lot of overlap.

http://www.ballisticsbytheinch.com/gaptests.html

Cheers.
 
Not to hijack your thread, but I have a 16" Trapper and would like
to know what factory .357 Mag ammo is best suited to the barrel.

I have Gold Dot 125 gr. GDHP and Black Talon 180 gr. SXT.

Thanks :)
 
It's possible. I know the link to the BBTI link shows a slight decrease with the longer barrel. But, not with every ammo tested, and that is just 1 barrel. You never know what will happen when you are comparing different guns. It is common to see 50-100 fps difference, sometimes more, even with barrels of the same length. Some barrels just shoot faster than others.

I'd just zero both at 75 yards and call it good. Neither would be off enough between 50-100 yards to matter.
 
I am a bit skeptical of a chart that shows velocity increasing up to 16", then abruptly dropping at 17", then increasing at 18". Maybe that powder charge got a second wind?

This seems to support the idea that the powder is all consumed within x inches, and then the bullet velocity drops as the bullet is slowed by friction, so a bullet fired from an x+" barrel will have less velocity than one fired from an x" barrel. But that is not the way things work. Even after the powder is consumed, the hot gasses it generated continue to expand and exert pressure. How long that continues depends on many factors, but it does continue well after the powder is consumed.

Jim
 
"Not to hijack your thread, but I have a 16" Trapper and would like
to know what factory .357 Mag ammo is best suited to the barrel.
I have Gold Dot 125 gr. GDHP and Black Talon 180 gr. SXT.
Thanks"
Click to expand...

I have tested the 16 inch Trapper and the 20 inch carbine with ammo from Georgia Arms (professionally reloaded). They used 125 and 158 grain GDHP 357's. With that ammo, the Trapper definitely groups tighter with the 125 grain ammo, particularly at 50 and 100 yards. In fact, the 158's scatter the shots (large group size) even at 25 yards and become laughable at 50 yards. The 20 inch carbine is decently grouped at 50 and 100 yards with the 125 grain GDHP. Not as tight as the Trapper, but still better with the 125 than the very poorly grouped 158 grain GDHP.

Unfortunately, the best groups obtainable with a scope and using a rifle rest at 100 yards with the 20 inch carbine and using Remington 125 grain SJHP is a few inches.

A few points to consider:
1. I don't have a chrono, so I don't have velocity data for any of that.
2. These are lever rifles with mag tubes and barrel bands. They are meant to be hunting rifles (with minute-of-deer sized groups), not marksmanship-demonstration instruments. They are prone to vertical stringing and uneven heating/cooling with varying rates of fire.
3. Interestingly, similar findings were observed with 125 grain 38 Special ammo vs. 158 grain 38 Special ammo at 25 and 50 yards.

I concluded that:
The 158 grain ammo groups lousy with these rifles and the 125 is noticeably better, but not perfect.

Never tried heavy stuff like 180 grain ammo.
 
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