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7mm Saum spraying


No i deer

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Hi all.

I've a 7mm Saum.

I tested some ammo at 100yds ready to shoot it at 1000yds.these loads shot superbly at 100yds.as good at it gets really.first up 180gr scenar I's sat on 59grs of N560.norma brass .br2 primer.

Secondly 162gr a max sat on 67grs of H1000.remmy brass and s&b primer..

It's a 28 inch barrel that's more of a sporting barrel.i shot it the weekend at 1000yds and it was bloody awful.at a guess my 3 siters were 6 to 8 inch group.after that there was no consistency whatsoever.i tried both loads and they were about the same.flaming crap.barrel was cold before each loads were shot.barrel measures 19.64mm at the shoulder from the muzzle thread.its not that much thinner than a varmint barrel.

Thoughts please.

No I deer.

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Better than this...just to give an i deer:

7SAUM 160g @ 2850, BC .5 ish,200 zero;10 mph wind: Drop/drift at 1000y :300/81 "

You don't give your MV (BC might be a bit differnt too) but we'll be inthe ball park,just for illustartive purposes.

Above means a 1 mph misjudgement  (of the aggregate wind -muzzle to target- of 1mph high on first shot and 1mph low on second will give dispersion of  8 inches in opposite directions,which added with 8 inches from sighting  could result in 20 inch dispersion for those two shots ( 8+8 plus plus 4 from sighters,though it could be more).

2" error would give an extra 32 (+) inches....gives some context to your 'bloody awful' or 'after a fashion'.     

More encouragingly,perhaps,in the spirit of Oscar Wilde : "Fashion  is so bloody awful,that we have to change it often".     :-)

 

gbal

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59grs of n560 pushes the 180gr scenar l's approx 2930fps

67grs of h1000 pushes the 162gr amax at 3038fps.

When testing these loads I fired 8 or 10 consecutive shots at 100yds one after the other and shot a sub 0.750 group in that wind we had 2 weekends ago

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So you have a 28" sporter weight barrel, that will put 10 rounds consecutively into 3/4" in wind, at 100 yards, and its burning 60+ grains per round ?

Take up benchrest....you have the luck of the devil.

 

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:P I double checked it was 8 consecutive shots.i'm sorry you gents are not inclined to think that it wasn' possible to shoot such a group but I did.the strong wind was mainly a headwind.it was really hard to hold the rifle still.i was very disappointed in the long-range performance after my 100yds testing.i wouldn' of bothered using it if I knew it would be crap.i did have some good shots but going by the overall finish it was luck.

 

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It' going for a rebarrel shortly.ive 2 options.a 28 inch Remington varmint profile or an f class 32 inch barrel 1 inch @ at the muzzle.i am tempted on the varmint as it' still useable across the fields.i am more for accuracy and portability rather that the extra velocity gained by the extra barrel length and it' too heavy to lug around.will the extra girth of the f class barrel gain noticeable accuracy. Cheers No I deer

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7 hours ago, No i deer said:

It' going for a rebarrel shortly.ive 2 options.a 28 inch Remington varmint profile or an f class 32 inch barrel 1 inch @ at the muzzle.i am tempted on the varmint as it' still useable across the fields.i am more for accuracy and portability rather that the extra velocity gained by the extra barrel length and it' too heavy to lug around.will the extra girth of the f class barrel gain noticeable accuracy. Cheers No I deer

Have you chronoed it?

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60grs on n560 gave 2970fps but it was a tad hot.off the top of my head i cant remember the ES.nearing single figures i imagine.i was getting faint ejector marks so I down loaded 0.2grs.the target shown was 59.8grs and still a litle warm so i  loaded them at 59grs.they were untested nor chronied.the 162gr amax load I also tried was on both accounts which shot superbly at 100yds. At 1000yds it was real bad.not what I am use too.it was very disappointing I can tell you.

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12 minutes ago, No i deer said:

60grs on n560 gave 2970fps but it was a tad hot.off the top of my head i cant remember the ES.nearing single figures i imagine.i was getting faint ejector marks so I down loaded 0.2grs.the target shown was 59.8grs and still a litle warm so i  loaded them at 59grs.they were untested nor chronied.the 162gr amax load I also tried was on both accounts which shot superbly at 100yds. At 1000yds it was real bad.not what I am use too.it was very disappointing I can tell you.

What have you shot at 1000 yards before? have you got a bench mark to work on? With any rifle..

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No not really .I've shot at 1000yds a lot of times to know the difference now.I shot my other 7mm and nearly doubled my scoring with the 7mm saum with the same bullet.it would certainly be a great barrel for a coldbore long shot stalking rifle that's for sure.

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2 hours ago, No i deer said:

Anybody have any constructive thoughts on my barrel choices

It's very difficult to give any input due the lack of information. You say shoot at 1k a lot but can't give an idea on what you are capable of shooting. If you can drill .5 Moa @1k on a regular basis and this rifle is far outside what you are genuinely capable of then you can take a step back and look at the rifle. Just because a rifle shoots well at 100 doesn't mean anything at 1000.

I'd check all your bolts are to the right spec and go back to the beginning of you load development. It's when you push the distance out you realise that nice little group you chose in the OCD wasn't the best choice.

 

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You maybe right on the ocw but faint ejector marks are not ocw for me. the opinions from a couple of ukv's experts seem to think it's the barrel type that is the problem.my other 7mm has a bartlein heavy varmint barrel that shoots superbly.better than I can :P

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