Oups, my 7x57 only has a 22,2" (56,6 cm) barrel

[Para Bellum]

I've just found out that my inherited and well appreciated Mauser 98 in 7x57 "only" has a 22,2" (56,6 cm) barrel.

RWS factory ammo data is from 60" (23,6") barrels.
I've never chrono'd my rifle.

Would I notice a relevant difference?

 

[Para Bellum]

fuhgeddaboutit

Just found that:
Barrel length v Velocity Calculator
http://www.bazoesoft.net/shots/barrel.htm

...but it seems you have to buy that software...


....and from what I have found on the www so far I am looking at 30ft/sec or 0ft/sec velocity difference betwwen a 22,2" and a 23,6" barrel (56,6 / 60cm). Sounds like a big fuhgeddaboutit.

 

[rbb50]

I always just figure about 30fps less per inch lost and of course it does not make much difference when it cronos at 2640fps to even think, Hey it could have been 2670fps with a barrel 1 inch longer

All of the bullets still go through the same dead center hole in the bullseye at 2640fps and I'm positive that is all I need

This is at http://www.chuckhawks.com/rifle_barrel.htm all the way down at the bottom of the article and has some other ideals on barrel lengths.

Velocity loss (or gain)

It is worth noting that the velocity figures published in ammunition brochures and reloading manuals are sometimes taken in barrels different in length from those supplied on many rifles. I have seen various estimates of how much velocity is lost (or gained) when a barrel is not the same length as the test barrel in which a cartridge was chronographed. Here are some of them.

The 2001 Edition of the Shooter's Bible states, in the introduction to the Centerfire Rifle Ballistics section, "Barrel length affects velocity, and at various rates depending on the load. As a rule, figure 50 fps per inch of barrel, plus or minus, if your barrel is longer or shorter than 22 inches." However, they do not say what category of load to which this 50 fps average pertains.

Jack O'Connor wrote in The Rifle Book that, "The barrel shorter than standard has a velocity loss which averages about 25 foot-seconds for every inch cut off the barrel. Likewise, there is a velocity gain with a longer barrel." He went on to illustrate this using a .30-06 rifle shooting 180 grain bullets as an example, so his estimate was obviously for rifles in that general performance class.

Other authorities have tried to take into account the different velocity ranges within which modern cartridges operate. The Remington Catalog 2003 includes a "Centerfire Rifle Velocity Vs. Barrel Length" table that shows the following velocity changes for barrels shorter or longer than the test barrel length:

MV 2000-2500 fps, the approximate change in MV per 1" change in barrel length is 10 fps.
MV 2500-3000 fps, the approximate change in MV per 1" change in barrel length is 20 fps.
MV 3000-3500 fps, the approximate change in MV per 1" change in barrel length is 30 fps.
MV 3500-4000 fps, the approximate change in MV per 1" change in barrel length is 40 fps.


The 45th Edition of the Lyman Reloading Handbook also has a table showing Center Fire Rifle Velocity Vs. Barrel Length. Their figures apply to barrels between 20 and 26 inches in length and agree with the Remington figures. The Lyman table shows the following approximate velocity changes:

For rifles with muzzle velocities in the 1000-2000 fps range, the change in velocity for each 1" change in barrel length is 5 fps.
For rifles with muzzle velocities in the 2001-2500 fps range, the change in velocity for each 1" change in barrel length is 10 fps.
For rifles with muzzle velocities in the 2501-3000 fps range, the change in velocity for each 1" change in barrel length is 20 fps.
For rifles with muzzle velocities in the 3001-3500 fps range, the change in velocity for each 1" change in barrel length is 30 fps.
For rifles with muzzle velocities in the 3501-4000 fps range, the change in velocity for each 1" change in barrel length is 40 fps.

The 43rd edition of the Lyman reloading Handbook gave some concrete examples of velocity loss for specific calibers and loads. The Lyman technicians chronographed some high velocity cartridges in rifles with barrels ranging in length from 26 inches down to 22 inches with the following results:

The average loss for the .243 Win./100 grain bullet was 29 fps per inch.
The average loss for the .264 Win. Mag./140 grain bullet was 32 fps per inch.
The average loss for the .300 H&H Mag./220 grain bullet was 25 fps per inch.

For standard high intensity cartridges in the same test, the Lyman technicians chronographed the cartridges in barrel lengths ranging in length from 24 inches down to 20 inches with the following results:

The average loss for the .270 Win./130 grain bullet was 37 fps per inch.
The average loss for the .270 Win./150 grain bullet was 32 fps per inch.
The average loss for the .300 Sav./180 grain bullet was 17 fps per inch.
The average loss for the .30-06/180 grain bullet was 15 fps per inch.
The average loss for the .35 Rem./200 grain bullet was 11 fps per inch.

 

[Scorch]

Gun writer Jim Carmichael did a similar test years ago, where he chronographed a bunch rifles and then cut the barrels down 1" at a time. High-pressure, large case, and grossly overbore cartridges showed more loss per inch, and low pressure rounds showed the least loss per inch. Low pressure, small case, and straight-wall cartridges showed the least velocity loss per inch of barrel removed. Bottlenecked cartridges showed more loss per inch as the barrel got shorter (makes sense), straight-wall cartridges were fairly constant. In 30-06-class cartridges (where the 7X57 fits in), the velocity loss was right around 50-60 fps average per inch, so that is a good approximation. Only a chronograph can show the truth, though.

Muzzle velocity does not necessarily correlate with velocity lost per inch, due to some of cartridges having very high chamber pressures (like the the 22-250 or the Weatherby magnums) and some having fairly low pressures (like the 30-30 and the H&H rounds), but often it does.

 

[rbb50]

If you reload and want to get into a bunch of neat math go here and study this page I wrote to find out the exact velocities you need to stabilize all weight bullets for your caliber.

http://www.thefiringline.com/forums/showthread.php?t=318179

What you might find is a shorter barrel works better with lighter bullets but will need to have a good size muzzle blast with heavier bullets to make them work also depending on the barrel twist rate of the rifle you are shooting.

Depending on the twist rate and velocity has a whole lot to do with how accurate your ammo will be.

You do not have that option if you buy factory ammo loaded for the twist rate in the certain length test barrel they use at the factory.

If you have that information they used and of course know your twist rate and approxamate velocity losses in the shorter barrel along with if your twist rate is faster or slower than the twist they used then you can use the math on my page to get exactly what you need to make it as accurate as possible and obtain the proper velocities to stabilize any weight bullet you shoot in any caliber if you do reload.

It has worked for me for about 30 years with fantastic results

 

[Para Bellum]

I prefer cartridges that are actually tested with actually availiably barrel lengths

It is worth noting that the velocity figures published in ammunition brochures and reloading manuals are sometimes taken in barrels different in length from those supplied on many rifles.

That's why I'd never use a .270 or 7x64. All the data for factory loads of these cartridges is for 65cm/26,6" barrels, but all manufactureres make these rifles only with 60cm/23,6" barrels. They only make magnum rifles with 65cm/26,6" barrels (.300 Winmag etc).

So if you think that your 7x64 or .270 outperforms a 7x57 by 10% or so because RWS's table says so, so must know that this table uses a 65cm barrel for the 7x64 and a 60cm barrel for the 7x57, .308, .30-06 and 8x57IS. You'd better check your barrel lenth because a .308, 7x57, .30-06 etc might perform as well or better than you 7x64 or .270 if both use usual factory barrels of 60cm/23,6".

That's why I prefer cartridges that are actually tested with actually availiably barrel lengths like the 7x57, .308, .30-06, .270 WSM (yes, that one 60cm!), 8x57IS, 9.3x62 etc.

 

[j.chappell]

That's why I'd never use a .270 or 7x64. All the data for factory loads of these cartridges is for 65cm/26,6" barrels, but all manufactureres make these rifles only with 60cm/23,6" barrels. They only make magnum rifles with 65cm/26,6" barrels (.300 Winmag etc).

You must be speaking of non-American companies as most over here use a standard 24" test barrel and the firearms companies market most of their hunting rifles in standard cartridges in either a 22" or 24" barrel.

J.

 

[rbb50]

Like the old 7.7x58mm Jap I reload for that had an original 26 inch barrel but now it is cut to 24 inch with a couple of other mods to help make it smooth shooting.

Just a little math in the reloading room and it shoots fantastic groups

 

[j.chappell]

As far as velocity loss it varies greatly. It will depend on a whole list of things. Even the same exact rifles chambered in the same cartridge with the same barrel length using the same load can vary dramatically.

You will find that the lighter the bullet the greater the velocity loss. I have a Ruger No.1 RSI chambered in 7x57mm with a 20" barrel. The one factory load that I use in that rifle has an advertised MV of 2390fps with a 175gr bullet when fired from a 24" barrel. I have crono'd that load at 2245fps for an average loss of 36fps per inch. This is not an entirely correct loss per inch though due to the fact that you lose differing amounts of velocity per inch. Say from 24 to 23 inches you may lose 50-60 fps but from 23 to 22 inches you may only loose 20-40 fps.

Your targets and game will not know that you shot that load from a 22,2" barrel and not a 23,6" barrel. You may be looking at 20-50 feet per second I would think.

J.

 

[Para Bellum]

You must be speaking of non-American companies as most over here use a standard 24" test barrel and the firearms companies market most of their hunting rifles in standard cartridges in either a 22" or 24" barrel.

Yep. RWS, Norma etc.
Right, just checked with federal, they measure the 7x57, .308, .270 and .300 Win Mag all togther with 24" barrels. That's much better to compare actually....

...and, yep again: I figured out, I'd have a max velocity difference of 30ft/sec. I use 173gr/11,2g bullets (RWS H-Mantel) in my 7x57.

 

[cole k]

Para Bellum, don't woory about the small stuff. Load her up and go kill something. You and the game will never notice the difference.

 

[Para Bellum]

So be it!

Para Bellum, don't woory about the small stuff. Load her up and go kill something. You and the game will never notice the difference.

So be it!

 

[cole k]

Smart move.

Smart move. Get to it.

 

[Major Dave (retired)]

Where do you buy bullets?

RWS H Mantel - not available @ Gander Mountain, Academy, or Mac's Gun Shop, here in East Texas. Where do you get them?

Sounds like a a good elk round, depending on MV.