7mm Mag double grouping ...

[bobinpa]

My buddy has a new Remington 700 in 7mm mag and it is double grouping BAD. I've seen this discussed before but never this bad.
This is a sporter rifle with a factory barrel with a standard magnum contour.
He is using a medium load of 67 grains of H1000 and 162 gr ELDXs. The barrel is a 1-9.25 twist and this target was shot at 100 yards with 3 different seating depths.
The scope mounts are Leupold back country ring mounts.
The scope mounts are new.
The scope mounts are tight.
The scope is new, and I'm going to leave the brand out of it just so this doesn't get into a brand hating thread.

If this was yours, what would you do, other than sell it or rebarrel it?

All help welcome
Thanks!

 

[Coyotefurharvester]

So NO adjustments made to scope during the seating depth test?

 

[Wolfdawg]

Start with the easy stuff:
- Check all of the screws ( base, rings, and action screws)
- try a different scope. New scopes can be bad.
- have someone else shoot it. I've shot many friends' guns that they insist can't group, and somehow they do better.
-try factory ammo.
- try different powder (Retumbo), bullet, primer, etc.

Lots of options before a re-barrel.
Just throwing out some options.
Wolfdawg

 

[bobinpa]

So NO adjustments made to scope during the seating depth test?

Correct. The scope was not touched at all. Fired 3, 3 shot groups without touching the scope.

 

[john 800]

I would try some basic factory loads, inspect the bedding/forend contact situation and try a different scope.

 

[Coyotefurharvester]

How much adjustment was used to zero scope? Or wasn't it actually zeroed?

 

[Orr89rocz]

Was a powder test done? Charge ladder? Why was 67 chosen? What velocity is it hitting? It could be charge weights or it hates those bullets.

 

[L.Sherm]

If it isn't i would start with bedding first.
Does it have one of those plastic stocks?

 

[bobinpa]

To answer some questions...
It has a plastic POS factory stock and factory bedding. The worst situation...
No idea how much adjustment was made to zero the scope prior to today.
The charge was selected out of a reloading manual as a mid level charge for a starting point.

It just seems really odd to me that the first and third shot in each group were close but the second shot was 2" - 3" away.
If it hated the bullets, why wouldn't it scatter them all around? It seems like a pattern but I've never seen a mid level powder charge double group to this extent.

If nothing else, maybe I can learn from this.

 

[358WCF]

New rifle, new mounts... Is the front screw touching the barrel threads? Magazine box bound?

 

[benchracer]

That target fairly screams bedding issue or barrel contact issue. OEM plastic stocks can often pass the dollar bill check, but flex enough during shooting to contact the barrel. I would be looking for an aftermarket stock with an aluminum bedding block, for starters.

Also, not sure what type of rest you are using during your testing, but rest type and placement could also have an effect on a flexy plastic stock. If shooting from bags, try placing the front bag under the action and see if the groups look different.

 

[bobinpa]

That target fairly screams bedding issue or barrel contact issue. OEM plastic stocks can often pass the dollar bill check, but flex enough during shooting to contact the barrel. I would be looking for an aftermarket stock with an aluminum bedding block, for starters.

Also, not sure what type of rest you are using during your testing, but rest type and placement could also have an effect on a flexy plastic stock. If shooting from bags, try placing the front bag under the action and see if the groups look different.

Shooting from an original Bald Eagle front test with Protektor model bumble bee in the rear. We did try moving the rest back, almost under the chamber, for the last group. Didn't make a difference....

 

[bobinpa]

Thanks for the replies so far. My original suspicion was either stock issue, scope issue or just try a different bullet.
So far the replies are confirming my suspicions. However if it was a stock contact issue, why is it acting predictable?
I almost want to have him try shooting a 6 shot group to see if it continues to bounce back and forth between 2 groups..
With the cost and availability of components, I'm thinking why waste them if someone has an idea I don't know of.

 

[Richard Jones]

Every time I've seen 2-grouping it's been scope/rings/bases related.

 

[Orr89rocz]

To answer some questions...
It has a plastic POS factory stock and factory bedding. The worst situation...
No idea how much adjustment was made to zero the scope prior to today.
The charge was selected out of a reloading manual as a mid level charge for a starting point.

It just seems really odd to me that the first and third shot in each group were close but the second shot was 2" - 3" away.
If it hated the bullets, why wouldn't it scatter them all around? It seems like a pattern but I've never seen a mid level powder charge double group to this extent.

If nothing else, maybe I can learn from this.

I would maybe try it in a different stock to be sure, or bed/stiffen up the factory one. Try different torque on action screws.
Only reason i suggest different bullet is that i seen similar in my 28 nosler with 165 sierra gamechangers. Alot of two close one way off regardless of charge and seating. I gave up on it. Maybe it was just too fast for that bullet. It shoots berger 180 and 195’s lights out.

 

[L.Sherm]

My nephew fought the same thing with his 22-250 untill I put a Boyd's stock and pillar bedded it for him now it shoots lights out.

 

[David Milisock]

My buddy has a new Remington 700 in 7mm mag and it is double grouping BAD. I've seen this discussed before but never this bad.
This is a sporter rifle with a factory barrel with a standard magnum contour.
He is using a medium load of 67 grains of H1000 and 162 gr ELDXs. The barrel is a 1-9.25 twist and this target was shot at 100 yards with 3 different seating depths.
The scope mounts are Leupold back country ring mounts.
The scope mounts are new.
The scope mounts are tight.
The scope is new, and I'm going to leave the brand out of it just so this doesn't get into a brand hating thread.

If this was yours, what would you do, other than sell it or rebarrel it?

All help welcome
Thanks!

I'm assuming as a modern rifle, it doesn't have iron sights, if it does and if you can shoot iron sights give them a try at 25, 50, 75 and 100 yards.

I'd do ONE THING AT A TIME! Make your decisions based on results.
Swop the scope to a known working scope.
Swop the stock, have it done by a knowledgeable person. It would be nice if you could borrow one.

If those two things don't make a significant improvement you've got a problem on your hands. I get this with older sporterized military rifles, almost always it's a stock issue. Even once the stock issue is resolved the rifle my only produce 2 and 3 shot groups.

 

[STOMP442]

Make sure the barrel is floated from forend to recoil lug. Remington has a nice habit of putting in some bedding pads at the forearm so that the barrel looks floated at first look but it is actually touching. This will cause all kinds of hell on target. Free floating should give you a bit more consistency at least but the tupperware stock needs to go asap. Those things are junk.

 

[Coyotefurharvester]

The stocks are junk but not usually that bad. I guess there can be a big difference in bad.

 

[BKA]

Another thing to consider - on page 3 of the link below, see Post #49

Lost and Confused regarding Load Development

I'm a relatively new to handloading. I've only done load development with hunting rifles with okay results. My go-to method was 1. Last up to published max looking for pressure to determine a safe place to test chargeweights 2. Shoot a ladder test to find flat velocity flat spot "nodes" 3. Test...

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