Effect of rifle modifications on load workup

[djfriesen]

What kind of impact on loads have people seen when swapping breaks? I went from a radial ported break on my Sako A7 to a side port break, which is quite a bit heavier. I know this will effect barrel harmonics, but I'm wondering to what extent.

I am hoping to not have to start over on load development. Is it reasonable to think the charge weight can stay the same, and just tweak seating depth to tune up the group? My instinct is that seating depth can be adjusted to offset any changes to the barrel whip.

Anyone with more experience than me care to chime in and either confirm my hunch or blow it out of the water?

 

[cohunt]

You'll have to shoot it to find out.....I always see a poi change with muzzle device change but often times the accuracy load wont change. It will be individual to your rifle combination though

 

[Dmagna]

I have had groups open and tighten based on muzzle devices. If you look at johnnys reloading bench on YouTube there is 4 or 5 hour long videos of him testing different things.

 

[Remmy700]

Have seen same thing. Groups open up, rule of thumb is any extra weight added or subtracted then starts playing with barrel harmonics. From my experience thought it is minuscule changes in powder charge to get u back to your node.

 

[WYO300RUM]

Great post topic. I had a radial brake on my Rem. 700 - 300 rum . When I switched to a 5 port side brake my groups with same load got larger. i wasnt too worried because I had the side brake cut 9/16 for a Sendero barrel that i bought from a good friend that I'm going to get installed on the rifle anyway and get action trued same time. Then, starting all over again....
The side brake is a MBM Lil Beast. Nathan's work is outstanding.

 

[Susquatch]

Anything you do like that will change the tune because it changes the way the barrel vibrates. Either for the better, the worse, or the same. Most likely it won't take much to get back on if it's worse though.