Thread: Grouping problem 338LM

These are some 3 and 5 shot groups. . .

What order did the 5 shot groups fall RB? Are all groups shot without scope adjustment?

Originally Posted by R93

What order did the 5 shot groups fall RB? Are all groups shot without scope adjustment?

I shouldn't laugh but that question is really going to rub salt in the wounds bit more head scratch
ing there red. I reckon it's the bipod mount but it's ok i have a spare spigot here we can drill into your stock....lol

It was a serious question, sorry if it poses a problem. Not my intention at all.

Originally Posted by R93

It was a serious question, sorry if it poses a problem. Not my intention at all.

Won't be real offence.I'm.just stirring him up lol

Hi Red is the barrel getting "warm" before the third shot ?
Looks like it could be a bedding & or slight fouling "issue"
Getting someone else to shoot it might help.

May not relate to this issue, but this was a interesting read on group analysis

Shooting - Group diagnosis

Have you built a solid shooting position? The 338 can have a "longer push" and cause all sorts of problems. Lying straight behind the rifle works for me; nice vertical muzzle jump.

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

What do you mean about different tecnique in sizing after firing, concerning moly 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.

Cool, will wait to see how James goes with it. I am still thinking bedding as it is classic 3 and 2 split.