Reduce barrel from 25" to 20" in .243 - Bad idea ???

[Lightyear 0]

Folks,

 

Can someone suggest what the effect will likely be if I reduce the barrel length of my .243 from 25" to 20" (1 in 10 twist).

 

As I understand it, I will lose some velocity on the rounds I use - Sako 90gr Gamepoint - but the length at the moment with the moderator is just a little unwieldy ! Sako suggest the muzzle velocity for the round is 3130 but not from what barrel.

 

I have seen it suggested that the velocity loss could be as high as 100fps per inch ??

 

Indeed I have also seen a suggest average 30fps per inch loss in velocity too !!!!

 

Obviously with a good job accuracy should not be affected, just POI ?

 

Cheers + ATVB

 

Philip

Edited June 5, 2009 by Lightyear

[bignoel 14]

i have a remmi 7 in 243 with a 17.1/2'' barrel no problems . it does what i tell it . now i got my scope mount sorted .noel

[Mr_Logic 5]

I would expect velocity loss to be around 200fps. Deker's short barreled Tikka is short of velocity that much against published loads.

 

Equally balance and handling are much better.

 

You should not lose accuracy, just velocity.

[sako243 0]

Hi

I don't want to get all scientific on this, but, if the bullet

manufacturer has spent countless money in development

of a bullet to do a certain job at a certain velocity, does the bullet

still do what it's supposed to do if you lesson it's velocity??

 

Just curious!!

 

Cheers

 

sako243

[Mr_Logic 5]

Yes, but to a slightly shorter range. Remember that a bullet loses velocity and energy relatively quickly, so bullet design is not for muzzle energy, but energy at typical shooting ranges.

 

In a 243, which has lots of penetration and requires good bullet placement on larger animals, the effect is minimal because penetration is still there with a slightly lower velocity, and good placement is still required.

[sako243 0]

I think i understand the penetration/velocity issue, but

what about expansion? Will the bullet still expand in the

intended manner and depth at a lower velocity?

 

Still curious!!

 

sako243

[RicW 67]

Folks,

 

Can someone suggest what the effect will likely be if I reduce the barrel length of my .243 from 25" to 20" (1 in 10 twist).

 

As I understand it, I will lose some velocity on the rounds I use - Sako 90gr Gamepoint - but the length at the moment with the moderator is just a little unwieldy ! Sako suggest the muzzle velocity for the round is 3130 but not from what barrel.

 

I have seen it suggested that the velocity loss could be as high as 100fps per inch ??

 

Indeed I have also seen a suggest average 30fps per inch loss in velocity too !!!!

 

Obviously with a good job accuracy should not be affected, just POI ?

 

Cheers + ATVB

 

Philip

I know that if I'm wrong in this Mr Logic will shoot me down, hopefully only metaphorically. I have long understood that you start to get problems if you reduce the barrel length to the point where the charge is not fully burnt when the bullet exits. Weeks and Hogg in Military Small Arms 1900-1977 state that when the Lee-Enfield barrel was cut down by 5" to produce the Jungle Riflethe resulting blast, flash and muzzle jump made the gun very unpleasant to fire. If that is the case it suggests to me that you might need to change your ammo to one with a faster burning powder. This is very much Mr L's territory though so I am ganging wary!

Ric

[Mr_Logic 5]

Ric you are correct. Increased muzzle jump, muzzle flash and decreased velocity are the result. You do gain balance though, and a moderator cancels the jump/flash to a large extent. It is indeed possible to change powders and get around the problem. Sadly, and I have limited experience here, you cannot do this for all bullet weights. 243 is a real problem because you need the heavy bullets for deer, and then you are using slower powders. My 223s both have short barrels, so I use Vit N130 and deliver good velocities with it, because it's fast burning. If I use a slower powder, I'm 200fps down on the published 24-inch load data.

 

Obviously it's a right PITA if you are using factory stuff too.

 

243 is a necked down 308, which immediately means that it needs a longer barrel than a 308 to burn the same amount of powder, assuming that powder burns at the same rate - all to do with volume.

 

Sako - a bullet will expand at a slower rate if the impact velocity is lower. Therefore, you will see less expansion, but my point was that with 243, due to normal terminal ballistics, the difference is minor and not worth worrying about. Rest assured, when the bullet arrives it's still gonna hurt!

[SNAP SHOT 194]

Why cut it at all, In a heavy bullet such as the 100g for .243, you need both velocity, and twist to stabilize the bullet, how ever if cutting short then a heavier bullet may tend not to stabilize fully and yaw its way to the target, accuracy wise you should notice no real difference at normal ranges, but velocity will be any where between 20 and 50 feet per sec down per inch cut off....

 

i'm extending my barrel length on the build from 22 to 24.5" for added velocity, also long range varminting where velocity is necessary to keep bullet drop minimal...

 

i would chop to 22" personally if need be, but your the one who's gonna shoot it,

 

 

good luck with it...

 

 

Snap.

[scarecrow243 24]

dont do it if the length of the barrel is causeing you a big problem change the rifle for one with a smaller barrel that has not been cut as others have said you will lose velocity and more muzzle flip most important long range shooting will be affected plus you ruin a gun and you cannot sell it until it gets re proofed

[Deker 3,478]

dont do it if the length of the barrel is causeing you a big problem change the rifle for one with a smaller barrel that has not been cut as others have said you will lose velocity and more muzzle flip most important long range shooting will be affected plus you ruin a gun and you cannot sell it until it gets re proofed

 

 

I understand the LEGAL side of selling cut rifles has now been resolved, largely down to Jackson Rifles. Legally there is now no need for reproofing...BUT many RFD still insist on it...sort of an insurance policy for them really!

[Deker 3,478]

If you are looking for a sensible, easy to use, everyday hunting rifle then forget all the hype and get cutting. My .243 was one of the first pre cut Tikkas in the UK and is under 20inches.

 

As Mr L has said, we have cronoed it and its down around 200ft sec on published figures. (NOT 200ft sec per inch..... 200ft sec TOTAL!) So?????? get used to it, it isn't going to chance your world. If you reload you will easily be able to find a powder/load to get the speed back...if you are that desperate.

 

25 inches is a flagpole!

 

It isn't a target tool, it is an everyday knock them down tool, it's well balanced and it works, I use 90g SP almost exclusively in it and it hits hard.

 

You pays your money and takes your choice!!

[cyclonebri1 8]

Just think about it, 25" is a flagpole, but for a target rifle it's normal.

 

What is game/ a rabbit? It's a friggin target, yes? Ok, pointability/balance comes into it but just remember you can shorten the gun anytime, you can't weld it back on. Live with it or change the gun, don't devalue it.

 

Not everyones view but it is mine

[Deker 3,478]

Just think about it, 25" is a flagpole, but for a target rifle it's normal.

 

What is game/ a rabbit? It's a friggin target, yes? Ok, pointability/balance comes into it but just remember you can shorten the gun anytime, you can't weld it back on. Live with it or change the gun, don't devalue it.

 

Not everyones view but it is mine

 

 

Chap

 

I think you are getting a littel mixed up....

We are not talking target and if anything 25" is short for a decent long range target rifle....

Hunting is NOT target shooting..target is repeatable known distances on the whole from the same position with a trigger so fine you breath heavy and it lets go, commonly prone and with a barrel that weights a ton and goes on for a fortnight, and you don't spend all day with a target rifle hung over your shoulder walking around a range looking for your next quarry.....a world different to hunting...cutting a hunting barrel to a manageable length probably enhances the value rather than devaluing it...many guns are being supplied with shorter barrels these days...the ENTIRE Tikka range of Hunters for a start...selling one rifle and buying another is likely to cost MORE than cutting the barrel!!

Edited June 6, 2009 by Deker

[cyclonebri1 8]

Just think about it, 25" is a flagpole, but for a target rifle it's normal.

 

What is game/ a rabbit? It's a friggin target, yes? Ok, pointability/balance comes into it but just remember you can shorten the gun anytime, you can't weld it back on. Live with it or change the gun, don't devalue it.

 

Not everyones view but it is mine

 

 

Chap

 

I think you are getting a littel mixed up....

We are not talking target and if anything 25" is short for a decent long range target rifle....

Hunting is NOT target shooting..target is repeatable known distances on the whole from the same position with a trigger so fine you breath heavy and it lets go, commonly prone and with a barrel that weights a ton and goes on for a fortnight, and you don't spend all day with a target rifle hung over your shoulder walking around a range looking for your next quarry.....a world different to hunting...cutting a hunting barrel to a manageable length probably enhances the value rather than devaluing it...many guns are being supplied with shorter barrels these days...the ENTIRE Tikka range of Hunters for a start...selling one rifle and buying another is likely to cost MORE than cutting the barrel!!

 

 

Like I said Deker, it's not everyones view but,

 

The point I'm making is that shooting rabbits, fox etc, particularly under daytime conditions has much more in common with target shooting than realised.

 

ie;

Shots almost always taken resting/prone/sitting/bipod etc?

 

Dialed in at ranges that would make free standing shots impossible?, considered rather than snapshots?

 

Everytime someone puts up a target on here and says "look at this. This is how accurate my shooting is". He's not taken them waving about in the wind, they are done under target shooting conditions.

 

Look how much folks spend trying to achieve a "better"trigger feel with aftermarket conversions etc, again all tipping toward target gear

 

 

Accepted that for lamping or 4x4 work the shorter gun is an advantage, but for me and a few others no doubt, 20-24"is a good useable length.

As said, if you want a carbine buy one, if you want something more swingable, buy a shotgun