The Firing Line Forums

Go Back   The Firing Line Forums > The Hide > The Art of the Rifle: Bolt, Lever, and Pump Action

Reply
 
Thread Tools
Old March 21, 2013, 09:14 PM   #1
valleyforge.1777
Senior Member
 
Join Date: June 2, 2011
Posts: 148
Is 357 velocity faster when leaving 16 inch Trapper or 20 inch carbine lever rifles?

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?

Last edited by valleyforge.1777; March 21, 2013 at 09:20 PM.
valleyforge.1777 is offline  
Old March 21, 2013, 09:28 PM   #2
the rifleer
Senior Member
 
Join Date: March 5, 2008
Location: Sunny California
Posts: 1,252
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.
__________________
There is no such thing as a stupid question, only stupid people.
the rifleer is offline  
Old March 21, 2013, 09:51 PM   #3
valleyforge.1777
Senior Member
 
Join Date: June 2, 2011
Posts: 148
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.]
valleyforge.1777 is offline  
Old March 21, 2013, 09:58 PM   #4
Adamantium
Senior Member
 
Join Date: June 6, 1999
Location: El Paso, TX
Posts: 992
You can actually see here that the 357 starts slowing down after 16 inches of barrel length.

http://www.ballisticsbytheinch.com/357mag.html
__________________
New gun, same ol' shot.
Adamantium is offline  
Old March 21, 2013, 10:16 PM   #5
big al hunter
Senior Member
 
Join Date: March 12, 2011
Location: Washington state
Posts: 933
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.
__________________
You can't fix stupid....however ignorance can be cured through education!
big al hunter is offline  
Old March 21, 2013, 10:43 PM   #6
jimbob86
Senior Member
 
Join Date: October 4, 2007
Location: All the way to NEBRASKA
Posts: 6,757
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.
__________________
TheGolden Rule of Tool Use: "If you don't know what you are doing, DON'T."

http://nefirearm.com/
jimbob86 is offline  
Old March 22, 2013, 01:00 AM   #7
Pathfinder45
Senior Member
 
Join Date: January 7, 2008
Posts: 915
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.
Pathfinder45 is offline  
Old March 22, 2013, 02:31 AM   #8
Metal god
Senior Member
 
Join Date: April 10, 2012
Location: San Diego CA
Posts: 1,969
Quote:
You can actually see here that the 357 starts slowing down after 16 inches of barrel length.
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 ?
__________________
As of this date 8-18-14 at 6:42am I became a proud grandfather I guess I'm officially old
Metal god is online now  
Old March 22, 2013, 03:41 AM   #9
Keg
Senior Member
 
Join Date: February 13, 2011
Location: Freestone County, Texas
Posts: 1,072
Question? Why would U wanna shoot 38's in a carbine? I would think 357's in both of em....
__________________
Hog Hunters never die........They just reload.........
Keg is offline  
Old March 22, 2013, 07:34 AM   #10
Jim Downey
Senior Member
 
Join Date: March 5, 2009
Posts: 203
Quote:
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 ?
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.
__________________
James Downey
http://www.ballisticsbytheinch.com/ - BBTI handgun cartridge research
http://www.guns.com/author/jim-downey/ - Guns.com where I'm a features/review writer
http://www.communionofdreams.com/ Communion of Dreams - my current novel.
Jim Downey is offline  
Old March 22, 2013, 08:10 AM   #11
SR420
Senior Member
 
Join Date: May 12, 2005
Location: Georgia, USA
Posts: 2,838
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
__________________
facebook.com/M14EBR.US
SR420 is offline  
Old March 22, 2013, 02:23 PM   #12
jmr40
Senior Member
 
Join Date: June 15, 2008
Location: Georgia
Posts: 5,891
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.
jmr40 is offline  
Old March 22, 2013, 02:57 PM   #13
James K
Staff
 
Join Date: March 17, 1999
Posts: 19,321
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
__________________
Jim K
James K is offline  
Old March 22, 2013, 07:48 PM   #14
valleyforge.1777
Senior Member
 
Join Date: June 2, 2011
Posts: 148
Quote:
"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"
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.
valleyforge.1777 is offline  
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 09:52 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2014 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.09817 seconds with 9 queries