7mm RM Grouping question

[Landyboy]

I've been trying to dial in my Browning 7mm Rem Mag and for this picture I am using Berger 168 Hunting VLD's it is a ladder load with Retumbo and each 3 shot group is 1grain of powder more. The 1st two shots of each group are nearly touching but the third is about 1 1/4 away. Its an Abolt sitting in a Bell and Carlson Stock 26" barrel. Velocity deviation is pretty good and I am waiting between shots the same amount of time.

 

[Dusty Stevens]

Thats typical browning groups. At least the wind didnt get you with the wait between shots

 

[Coyotefurharvester]

What is the twist rate in the Abolt and Abolt 11, my neighbor has one and I was wondering if they meet the 1/9 minimum for that bullet.

 

[Landyboy]

1:9.5 twist

 

[Creedmoor02]

I had a savage do that I couldn’t figure out what was going on so I sent it back to savage. This was when they were changing owners so I never heard anything, until I got the rifle back. Turns out they tightened the barrel lug and put a different stock on it. So I guess I would see if the barrel lug is tight?

 

[Dusty Stevens]

I had a savage do that I couldn’t figure out what was going on so I sent it back to savage. This was when they were changing owners so I never heard anything, until I got the rifle back. Turns out they tightened the barrel lug and put a different stock on it. So I guess I would see if the barrel lug is tight?

That cant be it but the hot glue may be a bit loose thats bedding it

 

[shoot4fun]

Don't misunderstand because I know we love the challenge of getting that rifle shooting bragging size groups. As hand loaders who shoot rifles it's how we're made.
Seems to me you would be better served by shooting a one-shot target every day for three days.
Overlay those three shots and see what your "hunting group" comes in at.
It's a hunting rifle and I like for a hunting rifle to deliver hunting rifle results. I don't really care if it shoots small groups; it's the first shot (cold bore) that counts.

 

[tsyarnall]

Dusty

 

[Coyotefurharvester]

You are a little slow on the twist rate, so you have poor groupings. My R700 was supposed to be 1:9, but measured 1:9.25 shot a couple close and then a "loose" one. Didn't understand until I checked the twist rate. I went to the 150 classic hunter, great groups easy to tune. A 1/8.5 is what I would rebarrel to for the 168 vld.

 

[Tommie]

Thats typical browning groups. At least the wind didnt get you with the wait between shots

Don't misunderstand because I know love the challenge of getting that rifle shooting bragging six groups. As hand loaders who shoot rifles it's how we're made.
Seems to me you would be better served by shooting a one-shot target every day for three days.
Overlay those three shots and see what your "hunting group" comes in at.
It's a hunting rifle and I like for a hunting rifle to deliver hunting rifle results. I don't really care if it shoots small groups; it's the first shot (cold bore) that counts.

Correct

 

[Tucker65]

I'm pretty sure the rifle didn't come bedded from the factory so my guess would be that things aren't coming to rest consistently as far as the action/stock goes between shots. You might check the torque on the action screws but if this is a wood stock without pillars or bedding you might just be chasing your tail. A good bedding job would most likely get rid of the flier as it looks like it wants to shoot.

-John

 

[Landyboy]

Its a B&C stock and it has pillars however I think the channel can be better, It's free floating but barely. I think I will open it up a little more to get the floating more constant. Then I will bed the lug and see what happens. I do agree I'm probably chasing groups when I should be looking at the first cold shot. It is getting better, when I started with Hornady ELD-x's and the factory stock I couldn't get it shoot a half decent group at all.

 

[HandgunHTR]

When you say "the same time between shots", how long is that? If it is always the third shot that opens the group up, I usually think of a couple of things:
1. The barrel is heating up to the point where POI is affected. To test that, you could do the following, shoot one round. Wait until the barrel is cool to the touch, then shoot another round at a different aiming point. Repeat that 2 more times for a three shot group at that second aiming point. Wait an hour and repeat the entire 4-shot process. Do that three times total and you will end up with a cold-bore group and three groups where the barrel is warm, but all shots should be relatively equal on the barrel heat. If the cold bore group is tight and at your POI and the other groups look like the ones above, then barrel heating is your most likely cause.
2. You are flinching on the third shot. Most folks can shoot hunting weight rifles chambered in magnum cartridges a couple of times before the recoil (or muzzle blast) starts to affect them in one way or another. It takes a special person to be able to shoot the big boys at the bench for extended sessions without it affecting their groups. I can honestly say, I am not one of those guys. I used to be, but I am not anymore. If you have a brake on the gun, that may not be the case, but muzzle blast does play into it as well. Double up your ear pro in that case to see if it helps (if you aren't already doing that).

 

[Landyboy]

Yea good point, my waiting time statement may be a little misleading. For each group I shot the 3 shots consecutively not really waiting much between shots, It was in between groups that I waited until the barrel cooled. I'm certainly not beyond flinching but I don't think I am, I usually only shoot 3, 3 shot groups with my bigger calibers for that exact reason. I do not have a brake on this one.

 

[rickhirsch]

Yea good point, my waiting time statement may be a little misleading. For each group I shot the 3 shots consecutively not really waiting much between shots, It was in between groups that I waited until the barrel cooled. I'm certainly not beyond flinching but I don't think I am, I usually only shoot 3, 3 shot groups with my bigger calibers for that exact reason. I do not have a brake on this one.

I shot 7mags all my hunting life. never had any luck with retumbo . people say it works them but for me its always just ok. imr 4831 s/c or r26 . i had a 270 short mag that did the same as yours . I took it hunting .
first shot was spot on . shot it for 9 weeks one shot on the same target 1.1/16 . next year changed barrel
to a 7wsm shoots 1/2 to 5/8 easy. that's with accubond's.

 

[K22]

Groups 1 and 2 are well within capabilities of a big game hunting rifle of that caliber. Consider the vital area of the game you are going to hunt and your field marksmanship skills - the maximum distance you can hit that area in a field shooting position.

If you're shooting sustained shots, then I would expect the 3rd shot to vary from the first two in a caliber of that magnitude.

 

[Tommie]

What kind of 100 yard groups are you expecting with your Browning A-Bolt in 7mm Rem mag? Just asking.

 

[Landyboy]

Like to get sub MOA but I understand that may not be possible.

 

[JEFFPPC]

IMR7828

 

[Pete Wass]

Years ago I was at my club and a young lad cam there with a Rem 742 in 30-06. He had recently bought the rifle and wanted so sight it in. He had a box of factory Remington ammo and some reloads. He shot the new box first and had groups pretty much like these then began to shoot the reloads. All stayed about the same until his last three shots, which went into a hole about .050" i would estimate. So, I ask him, "do you know what for powder and bullets were in those last three shots"? Of course the answer was NO. Point here is there might be a magic formula for your rifle but it may take a lot of work to find what it is. I've had benchrest rifle barrels that would only shoot one bullet-powder combo so it isn't beyond reason that the same could be true for your rifle. A truth was spoken here about the first shot coming out of a cold barrel though. With a hunting rifle, the first shot is the most important, usually, so one shot every three days is pretty good advice.