Can anybody shed light 0n what effect will be made on accuracy, reducing the length of a barrel from 21" to about 17" or 18", I am aware that I will be loosing some velocity, but if accuracy is unaffected then I would like to try it.

The reason for this is that I want to fit an ASE UTRA JetZ moderator, this will extend the length of my barrel by 150mm.

Thoughts and observations would be appretiated

the length of BBL does not dictate its accuracy.
your rifle could be shooting 1.5" groups and you cut 1" off and it goes to shit. cut off another 1" and groups got to .5". harmonics play a part. bbl rigity as well.
Steyr scout rifle w/ 19" BBls regularly outshoot 26" BBl Remington PSS heavys.

Acuracy may get better or may get worse.
What is the gadget you mentioned ?
...tj3006

The condition of the crown will potentially have a large impact on the accuracy of your rifle after any length of barrel is removed. Otherwise there might be other changes, for better or worse. No one really knows exactly why some rifles shoot better with one bullet or load vs. another. Frankly, if you're happy with the way it shoots currently, you might want to consider rebarrelling rather than 'chopping off' the end of the current barrel.

quote:

Originally posted by Thomas Jones:
What is the gadget you mentioned ?
...tj3006

probably a can.
so unless your going to use the can to comply with some law then its pretty useless with a 7mm-08. i would think you'd have to use the heaviest bullets at a subsonic velocity to achive suppression of the bullet itself.

As a general rule, the shorter the barrel, the stiffer it will become, consequentially with decreased harmonic vibration with the shot and therefore improved accuracy.

Accuracy will depend mostly on the quality and condition of the crown, however.

The ASE Utra JetZ, is indeed a sound moderator, here in the UK alot of shooters are using them for several reasons, they suppress the discharge noise of a shot to reduce disturbance not only to the public (especially usefull at night for pest control) but also in a stalking area to increase cull numbers on one outing, they negate the need for wearing ear defenders (this complies with our Health and Safety acceptable noise levels), many uses shoot more accurately with them (reduce muzzle flip, but more importantly I believe stop users from flinching from the shot because it is quiter).

At one time in the UK it used to be hard convincing the police to let us have a moderator but now they almost always let us have one.

And that scout bbl is skinny, but stiff vs longer tube of same O.D.

I would say the loss in speed is about 100-150fps no more. Accuracy, may get better but doubt worse as barrel gets stiffer, all else equal.

nightwalker,
Cut it off. the drop in velocity should be little as a 7/08 burns most of its small charge relatively fast and any drop in velocity would be great for you since you are using a can.
As for the crown just keep it clean and use a drill to polish if needed. I think Saeed proved that a damaged crown only effects accuracy to a small degree.
I doubt you are shooting competively so sniping vermin at night does not require pintpoint accuracy.

Lop that barrel off and have at it. no worries.

quote:

Originally posted by nightwalker uk:
... many uses shoot more accurately with them (reduce muzzle flip, but more importantly I believe stop users from flinching from the shot because it is quiter)...

I believe that is a very important point. Recoil does not cause accuracy problems per se, as the bullet is long gone by the time the recoil is 'felt'. However, anticipation of recoil, especially heavy recoil, can cause the shooter to 'tense' or 'flinch'. The noise and muzzle flash can also cause / contribute to this. Contrary to what some people believe, that those that 'flinch' are 'wimps', it's a conditioned reponse that one does not have complete conscious control over. It's more like 'jumping' in response to an expected loud noise - although in this case the 'reaction' is in anticipation of the loud noise / flash / recoil.

I have a 20" varmint barrel in 7mm08 and it is my most accurate rifle. When you shorten the barrel the harmonics change and sometimes accuracy improves. I shoot 140 TSXs at 2840 and you will not lose much by going to 18".

Well, they make Thompson/Center arms pistols (Contender/Encore)in this caliber (14/15" barrels?) and I never heard anybody complain about accuracy simply because of thier length.
Although it may not apply in your case, usually what I hear when it comes to this issue is why not just get a better/different caliber suited for the shorter length instead of wasting powder...?
Good luck.