Thread: Grouping problem 338LM

Hi folks, got me a problem and am hoping someone can come up with a fix.
Brand new Savage 110 FCP in 338 LM, Sightron 8-32x56 shooting off a bipod and rear bag at 110yds. 285gr Hornady projectiles,H1000 working between 90-93grs, Norma brass.
Problem:- One shot jumps out of a group of 3 shots( by about 1-1 1/2") and sometimes its 2 shots jump out of a 5 shot group, the others shots are touching or pretty close.
I've checked all scope mounts, rail mounts, action screws and the free float is well clear. The powder loads are all exact, and round is concentric to within .001-.003.
Any and all comments welcome, cheers, Red

If everything is sweet that you can control then my guess would be she needs some attention in the bedding department.

Fire a couple groups again but on a cold barrel, say 5-10 mins between shots. If you get the roughly same pattern it will most likely be some action movment.

Possibly bipod jump, make sure your technique is perfect, preload the bipod so that when it recoils it doesn't jump. Otherwise borrow a benchrest and do your accuracy testing there.

Originally Posted by Herbmiester

Possibly bipod jump, make sure your technique is perfect, preload the bipod so that when it recoils it doesn't jump. Otherwise borrow a benchrest and do your accuracy testing there.

Mind my ignorance here but on all the slow motion shots i have ever seen of guns being fired i can clearly see the projectile and the gases have exited the barrel long before any sort of recoil happens. So is the issue with bipod jump more to do with the shooters stance and grip setup BEFORE they fire the round rather than AFTER the round has been sent?

Just saw the groups , vertical can be caused by the butt slipping against your shoulder , you could try some one else shoot your rifle to see IF you or the rifle has the issue .

Are you using Moly coated bullets ? , as they show a split group like that until fouled , they also require different technique in sizing after shooting.

You are no doubt aware that in the 338LM calibre , brass is critical , as the pressures are very high , most shooters get 8-10 reloads out of Lapua made brass in this cal , BUT only 1-2 reloads out of Norma made brass , as such that would suggest to me that the norma brass is not as tough , ie cannot handle the pressure as well , this may show up as losse primer pockets & inconsistant neck tension ?

Later Chris

Originally Posted by Towely

Mind my ignorance here but on all the slow motion shots i have ever seen of guns being fired i can clearly see the projectile and the gases have exited the barrel long before any sort of recoil happens. So is the issue with bipod jump more to do with the shooters stance and grip setup BEFORE they fire the round rather than AFTER the round has been sent?

Thanks to the lack of an edit button my badly worded post is doomed to stay..

So heres goes again.

Once the round has left the barrel (which happens before any sort of recoil) then any poor follow through that happens is a result of bad grip and bad pre-shot setup/stance right? What i want to know is how can bad follow through effect a round that is already on its way? If the round kicks off when the reticle is where you want it then anything that happens after this event should have no bearing on where your round is headed should it? I hope that reads better than my last post.

Originally Posted by Towely

Thanks to the lack of an edit button my badly worded post is doomed to stay..

So heres goes again.

Once the round has left the barrel (which happens before any sort of recoil) then any poor follow through that happens is a result of bad grip and bad pre-shot setup/stance right? What i want to know is how can bad follow through effect a round that is already on its way? If the round kicks off when the reticle is where you want it then anything that happens after this event should have no bearing on where your round is headed should it? I hope that reads better than my last post.

Perhaps to do with how the muzzle blast is affecting the bullet immediately after leaving the barrel?

R93, take no notice of that stirrer Horihunter, he's the sucker thats going to do the next lot of groups

The bottom group was the 3 together 1,2,3,the other 2 were 4,5. Can't remember which way that other 5 shot group went.

ChrisF, no moly. It is Norma brass and I'm x2 and x3 reloads so far without problems, fingers crossed it lasts.

KG, the groups were shot pretty much one after the other, with pauses inbetween. Rifle wasn't feeling hot till the finish really, and not that hot either. Perhaps a bore snake pull through between groups might help.

I'm keen to see how Hori goes with it, but I'm thinking that it is me. I have been in the habit of writing down the speeds as I go, which means I'm disturbing my cheek and butt weld each time. That can't be good for consistency.

Sling stud hitting rear bag?

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Originally Posted by CreepingDeath

Sling stud hitting rear bag?

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Whats your theory on this one sir?

Originally Posted by R93

Whats your theory on this one sir?

Haha im ready to be shunned for this but aparantley the stud hitting the bag in a different way each time the rifles fired(especially heavy recoiling rifles) can alter poi. Now this isnt my theory but have two freinds that shoot f class and alot of long range who swear by this.



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I fire oodles of rounds the same way. I think it is worth looking at, not shunning as it may have a ton of merit. You see some BR shooters allow the rifle to freely recoil straight back by lying on top of the stock, not behind it.

There is quite a bit of stuff that has been written about making sure rifles recoil in 'exactly' the same way each time. There was a really interesting article on here a while back about some guys in the US who used to shoot amazing groups in a great big building (static environment), they talked a about the way they held the rifle each time affecting group sizes.

I would check to see the brake is tight & shows no sign of getting in contact with the bullet .

It seems you have checked all screws etc , I would pull the bipod off and fire it off sandbags front & rear , and also use the free recoil style of shooting IT , BUT be aware that you may have large groups at 100 & at 500 they are much smaller moa relative , I think some times it takes the big pills a bit longer to settle down .
In a Sako TRG-41 , I found it was not that impressive at 100m ( approx 1 moa ) , but at 500 it was sub 0.4 moa ( 2.25 inche groups ) , just some thing to think about .

Later Chris

I may be different to most, but I only allow the butt to rest against my shoulder and apply some cheek pressure, when lying prone. I do not load the bi-pod in any way if using one. I manipulate the trigger with fore finger and thumb pressure only. I never grasp the grip with my whole hand. I have a sling on my rifle and will remove it for load testing and such. I will remove the stud nxt time I am having a play and see if there is any difference. Cheers CD it may account for the rare wtf moments I get.