Barrel Chop Screwed Up Accuracy

[longrange13]

Had my tikka 223 cut and threaded by a well known gunsmith. It is has 17” of exposed barrel. It totally screwed up the accuracy. Anyone have this happen? Previously it loved the 77tmk and smk, threw them both in about a 1” 10 shot rapid fire group. Now it groups around 2+ moa and pretty random.

 

[pods8 (Rugged Stitching)]

If you believe in optimal barrel time nodes then the different length can move you out of the node that your original powder charge was giving you. Might need to +/- the powder charge a tad. What are your load specs?

 

[RockAndSage]

OP, unless the smith screwed up the crown and left dings or worse in it, or your action screws aren't properly torqued down, there's a pretty high likelihood changing the barrel length put its accuracy nodes in different places with the load you have been using, as mentioned above. Before going there though, check the crown, check the torque on the action screws, maybe give it a patch down the barrel to see if anything comes out, and also check to make sure the scope's mounting is all properly torqued, before you mess with your loads at all. It's a bit like when your car won't start - think common, easy things first before jumping to more unlikely but severe problems. Foot on brake, battery cables fastened properly, battery works, etc, before thinking it may be the computer or starter.

 

[seand]

Could be the barrel opens up where they cut it, was tighter at the previous muzzle location.

I bought some lead slugs from brownells to try and check for this before I send a few barrels in to be cut and threaded. Haven’t done it yet and have no experience with it.

Just a thought.

 

[longrange13]

If you believe in optimal barrel time nodes then the different length can move you out of the node that your original powder charge was giving you. Might need to +/- the powder charge a tad. What are your load specs?

I’ll have to check when I get home but I think I’m around 24.9 grns Varget, seating depth to mag length can’t remember the length off the top of my head, lapua brass, and 77tmk.

 

[BrBa]

I would first take a close inspection of the crown if you are able.

 

[Formidilosus]

Cutting your barrel a couple inches isn’t changing a “node” from 1 MOA to 2 MOA. Y’all need to stop going down rabbit holes.


Check assembly first- front to back on everything. Ask the smith if he took the barrel off the action.

 

[Coopsdaddy]

Would taking the barrel off affect it,just curious.
Seems a lot leave the action on and some want to take apart.

 

[Steve300xcw]

I've cut a few barrels with just a zip wheel and even with a VERY haggard looking crown they didnt shoot all that bad.

Now it groups around 2+ moa and pretty random.

Random to me means you got some stuff loose on the gun.

 

[SloppyJ]

Check your action and your scope.

 

[JohnJohnson]

I had a 24" Bartlein barrel (6.5CM) cut down to 16.5" and it shot just as good or better. If your groups opened up THAT badly I'd be checking the moving parts and screws of the system.

 

[ResearchinStuff]

Check for barrel contact on the forend. Check for loose muzzle device.

 

[Castle Rock]

Would taking the barrel off affect it,just curious.
Seems a lot leave the action on and some want to take apart.

It would if it wasn’t put back on tight

 

[HandgunHTR]

Had my tikka 223 cut and threaded by a well known gunsmith. It is has 17” of exposed barrel. It totally screwed up the accuracy. Anyone have this happen? Previously it loved the 77tmk and smk, threw them both in about a 1” 10 shot rapid fire group. Now it groups around 2+ moa and pretty random.

You say "cut and threaded". What muzzle device (or suppressor) do you have on it that wasn't on it before? Have you shot it without that?

 

[robtattoo]

I've cut a few barrels with just a zip wheel and even with a VERY haggard looking crown they didnt shoot all that bad.




Random to me means you got some stuff loose on the gun.

I've done quite a few with a hacksaw & 'recrowned' them with a stone grinding ball in a cordless drill. Never had one yet that ended up less accurate than stock.
It's 99.999% not your cut & crown.
Something is loose or not seated right for sure.

 

[Wrench]

Shortening typically increases accuracy due to stiffness improvement.

Threading on a device could be the culprit. Is it hamb fisted tight? How big is the through hole?

 

[Steve300xcw]

I had an issue in the past with the barrel not seating onto that recoil lug in the stock properly. That made it stupid for a few