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I need to chop a barrel back on a semi auto, the ideal would be around 12-12.5" for the application and it will be fitted with a sound moderator however my concern is will the rifle still cycle. I have gone back to 14"-14.5" in the past with Winchester X Subs however this will be with CCI HP Subs. Is anyone running a short barrel on a S/A's with a mod and seeing cycling issues, or indeed shooting successfully?

My only experience of 12" barrels is .22LR uppers with solids and they cycled perfectly and I am not keen on the idea of having a rifle that no longer cycles as it will mean bolt lightening which is an area I have no experience with when it comes to rimfire rifles.

My BAR .22 is 12" - cycles everything - currently using a SAK suppressor and SK std club ammo.

My 10/22 had a 12.5" VQ barrel, fitted with SAK mod, ran well with standard CCI.
15-22 with 12.5" with Hardy mod and also with Atec Wave, no cycling issues with CCI standard, or Eley.

My CMMG is back to 12.5" runs just fine. Tried it with CCi std and a B&T mod. Ran fine

Every single .22 semi-auto pistol cycles reliably with a 4-5" barrel, even with subsonic match ammunition. With a bit of tweeking of the springs etc. I can't see any reason why a short barrels rifle couldn't be made to.

1066 wrote:Every single .22 semi-auto pistol cycles reliably with a 4-5" barrel, even with subsonic match ammunition.

^^^^ this

Good point chaps

The rifle has to be as short as possible within legal constraints and I am considering back boring the barrel and machining it with a spigot and thread set back by another 25-30,0mm or so, then vent the bored section of the barrel to act as the first stage of the sound moderator. This would reduce the overall length even further, assuming the barrel is meaty enough to cope with such a reduction. I will have to have a measure up on Monday.

It has set me thinking about the free bore boost effect again :)

Barrels cut back too much then not working the action are more an issue with gas vented guns, not blowback types, from my understanding/experience.

Not chopping back a Nylon 66 per-chance??

Ovenpaa wrote:Good point chaps

The rifle has to be as short as possible within legal constraints and I am considering back boring the barrel and machining it with a spigot and thread set back by another 25-30,0mm or so, then vent the bored section of the barrel to act as the first stage of the sound moderator. This would reduce the overall length even further, assuming the barrel is meaty enough to cope with such a reduction. I will have to have a measure up on Monday.

It has set me thinking about the free bore boost effect again :)

I had a similar idea years ago. Back bore the 10/22 .920 barrel. Insert baffles from scrap suppressor. Add an end cap. Instant built in moderator.

Got Joe at Gunshop Barnet to do it. He was so impressed he went on to make a batch to sell. The Met charged him with some proof act offences. He won but only after a long trial.

breacher wrote:

Ovenpaa wrote:Good point chaps

The rifle has to be as short as possible within legal constraints and I am considering back boring the barrel and machining it with a spigot and thread set back by another 25-30,0mm or so, then vent the bored section of the barrel to act as the first stage of the sound moderator. This would reduce the overall length even further, assuming the barrel is meaty enough to cope with such a reduction. I will have to have a measure up on Monday.

It has set me thinking about the free bore boost effect again :)

I had a similar idea years ago. Back bore the 10/22 .920 barrel. Insert baffles from scrap suppressor. Add an end cap. Instant built in moderator.

Got Joe at Gunshop Barnet to do it. He was so impressed he went on to make a batch to sell. The Met charged him with some proof act offences. He won but only after a long trial.

I believe this exact job - boring out 10/22 barrels to completely contain a moderator was cited in the Jackson moderator shenanigans.

Here you go - an interesting read:-
http://jacksonrifles.com/zz-silencers/f ... idence.pdf