Changed press and accessory rail on bipod - lost sweet spot load?

[JoeZA]

Hi guys,

I recently changed from a RCBS rock chucker turret press to a Forster Coax press and installed an accessory rail in the stock so that I dont have to mount the bipod on a sling swivel.

All my components and specifications stayed the same: brass type, new brass prepped the same way, primers, lot of powder, headspace, bullet type and COAL.

However the rifle suddenly does not group anymore on that load? The runout on the Coax is better. Can the installation of an accessory rail affect the dynamics of the rifle so much? Or is it the new press?

 

[deadwooddick]

Can the installation of an accessory rail affect the dynamics of the rifle so much?

Likely not the rail installation, if correctly done… i.e., fitment screws not interfering w/ barrel free float. Did you goto a different bipod ? Different brands typically need different techniques… loading the legs vs. unloaded, etc.

 

[338 Mollett]

Partner I can't say I have a 6 brx that has done the same thing.Won a few matches with it,and the last match I was in I should have used a Daisy bb gun.I'm going to do a little load work today,we'll see.Good luck !

 

[tac284]

You made sure that the screws that hold the accessory rail on didn't go all the way through and touch the barrel right? Just asking, seen it done before.

 

[JoeZA]

No screws going through the stock / touching the barrel....

 

[artbosco]

Hi guys,

I recently changed from a RCBS rock chucker turret press to a Forster Coax press and installed an accessory rail in the stock so that I dont have to mount the bipod on a sling swivel.

All my components and specifications stayed the same: brass type, new brass prepped the same way, primers, lot of powder, headspace, bullet type and COAL.

However the rifle suddenly does not group anymore on that load? The runout on the Coax is better. Can the installation of an accessory rail affect the dynamics of the rifle so much? Or is it the new press?

If the load was tuned to your barrel, and the barrel hasn't been replaced, LOOK to what you changed as one of the culprits or a combination of culprits.

You can go back to what you were doing before things went haywire or look at the things that can cause a .001" or more movement at the rifle which projects a 1/4" POI movement or more on the target over 100 yards.

Any accessory that moves .001" or more has never been a favorite of mine. The more things that rattle the larger groups become. Look hard at the play or sloppiness in the accessory rail.

 

[jlow]

Was your load developed at the same temperature as you shot recently when you lost your sweet spot. Depending on your components, especially powder, your MVs could have significantly changed and that together to where you are on your sweet spot and it's width could be the culprit.