Winchester Model 70 Double Grouping

[Bado20]

Today while doing load development on a Winchester Model 70 Featherweight in 6.5 PRC I had a bit of an odd result. The rifle’s 10 shot group was not round… it was two clusters of 5 with a gap between them. Normally I would say this is a bedding issue, but the same rifle/bases/rings/scope shot around a 1.1 10-shot group with the Norma Whitetail factory ammo. Has anyone seen this behaviour before?

Further info: bases are Burris tactical steel bases, rings are cheap but have about 4000 rounds on different guns without exhibiting any issues, scope is Vortex LHT 3-15x42. The barrel has been confirmed to be free floated and the action screws were checked after the range session and are still torqued properly. I was shooting 3-shot groups and then letting the barrel cool, all to the same point of aim. The shots would vary from side to side throughout 3-shot strings, without me breaking position. Parallax was adjusted prior to shooting the groups and not touched between strings.

Handload that double grouped is Norma brass, CCI BR-2 LR, 142 ABLR, COAL 2.88 inches, 60.5gr Ramshot Grand.

 

[user2026]

I'm far from a gunsmith, but experienced similar issues last spring when my rifles stock cracked. I would repeat with the norma loads, and handloads again. Could just be dumb luck, but that would be very lucky. Did it shoot one "group", and then the next? Or did it randomly shoot one shot left, then 2 right, then 2 left etc? I guess what I'm asking is did something happen in the middle of the 10 shots that made a shift. If your scope rings aren't true, I've had scope adjustments "stick" and take a few shots before the scope adjusts. Lapping has always fixed that for me.

 

[Bado20]

I'm far from a gunsmith, but experienced similar issues last spring when my rifles stock cracked. I would repeat with the norma loads, and handloads again. Could just be dumb luck, but that would be very lucky. Did it shoot one "group", and then the next? Or did it randomly shoot one shot left, then 2 right, then 2 left etc? I guess what I'm asking is did something happen in the middle of the 10 shots that made a shift. If your scope rings aren't true, I've had scope adjustments "stick" and take a few shots before the scope adjusts. Lapping has always fixed that for me.

It was randomly shooting a couple left, then a couple right, then back left again. I think you’re right, I’ll give the Norma factory ammo another try and see if it’s still consistent. I’ll also pull the action out of the stock and see if there’s a crack.

Better quality scope rings are another thing to try, I didn’t adjust the scope this range session though.