[firemedic1424]

Anyone with a suggestion on a recent problem with reloading 160 gr 7mm Remington Magnum. This may be a Acuubond problem or a problem with me. I base my reloads of the data in the most current Nosler book. I don't have the data in front of me, but I worked a load up for my 7mm rem mag. I generally load in 5 shot increments. Therefore, I shoot 5 shots at the bench. If I get good results from a particular load. I will return to the bench another day to confirm the grouping of the load. I test everything @ 100 yards. I chose my load (1/2") groups. I loaded several more rounds and proceeded to shoot the gun in. At 200
yards the group open up as much as 10-12" all over the target. I have checked bases, rings, scope,etc. What the heck? I need a corse of action, thanks.

 

[leverite]

What's the twist on your barrel? Is it too slow to stabilize the heaviest bullets?

 

[firemedic1424]

HHHMMM, good question. It's a Ruger M77 Hawkeye Stainless, I would assume 1:10

 

[broom_jm]

After getting that huge spread at 200, did you go back and verify that you were still at 1/2", at 100 yards?

 

[firemedic1424]

Absolutely, it was right on the money. I know the bullet might begin to react differently after the 100 yd mark, but- That Much?

 

[firemedic1424]

I agree with you on distance, this is why I bow hunt as well. I hunt in south texas and he large oat fields sometimes require a stretch of a shot at times.

 

[broom_jm]

Yeah, you should be able to shoot those Accubond bullets out to at least 300-400 yards, without losing accuracy, like that. I would get in touch with Nosler and ask them if the have any ideas...very strange.

 

[leverite]

HHHMMM, good question. It's a Ruger M77 Hawkeye Stainless, I would assume 1:10

I'm not familiar w/ the 7mm, but Ruger is usually pretty good w/ their twist rates for heavier bullets.

 

[bsn]

Do you have any room to push them a little harder or maybe try some 140s.

 

[firemedic1424]

I will try a new bullet @ 160 gr. and see what the result is. I really want to stay with 160 gr in order to have the readiness for potential elk hunting. I may switch to partitions and work with and tried and true champion of a bullet. I just love the idea of a ballistic tip that will hold toether and retain it's weight and energy.

 

[zb338]

Going from a half inch to ten is a lot, but don't expect to keep
getting a minute of angle all the way out. I have found that
shooting at 100 yds. is a lot different than shooting at 200 yds.
Groups tend to open up based on wind, mirage and all the
variables.

Zeke

 

[firemedic1424]

Thanks, but I strive to shoot in as optimal conditions as possible. The day I shot these reloads was 66 degrees, light light wind, low humidity, and mostly sunny. I understand the outdoor variables play a key role, but I don't think this is the case especially 100 to 200 yds with the group opening almost 10 inches.

 

[mattsbox99]

Any chance you are shooting through something? Years ago I was shooting some rimfire at an unmowed range. I was shooting pretty good groups, but when I tried to shoot through some grass at the targets, bullets were all over the place.

 

[firemedic1424]

Thanks, but it is a freshly mowed meadow. Keep trying folks- good stuff.

 

[spitfire_er]

hmm.... I am shooting that same bullet/caliber, but have not taken it to 200 yet on a range. I developed the load for mine (0.378" 5 shot at 100) and called it good. I'll have to take it out to 200 one of these days when the weather clears up. Maybe this weekend I'll take it coyote hunting and see how it does.

I've been too busy with other rifles, so this one has been on the back burner when I called it "good enough for now".

What's your load data?

 

[big dan]

it's probably due to the length of the bullet/rate of twist. i recall reading an article about the 300wm and they were having trouble with the 180gr accubond stabilizing. it turns out that the rifle had a slower than spec'd twist rate. they do vary...

i also recall reading an article some years ago about the ballistic tip bullets and the subject of why no 160gr bt in the 7mm was addressed and at that time they said that there were stability issues due to the length of the bullet with the industry std. twist rates.

 

[leverite]

SHilen recommends a 1 in 9 twist for any bullets heavier than 140 grains in 7mm.

Bet your 1 in 9.5 twist rate is your problem. 140 grain bullets can perform well on elk...lots of elk taken w/ 140 grain, 270 Win bullets. Try 140's and see how they shoot.

 

[gunpa]

I really wouldn't think your twist rate is that far off. If it was you should see some evidence of keyholing with those big groups. That is what unstabilized bullets do. I'd make sure they are moving fast enough and I would try another bullet design with the same components, something should show up. Good luck!

 

[gunho1954]

twist rate

I really wouldn't think your twist rate is that far off. If it was you should see some evidence of keyholing with those big groups. That is what unstabilized bullets do. I'd make sure they are moving fast enough and I would try another bullet design with the same components, something should show up. Good luck!

i agree 100 %.-my 7mm rem will shoot up to 175 smk and 162 accutip which look like darts without flights.you dont say what load you are using as far as velocity.if you are only pushing them out at a modest velocity,you may have probs down range,but not to your extent.--wind,unseen obstructions and double the range,add fustration and you can get a 10" group.if those holes on the target are round ,thats probably your problem. a gun that shoots 1/2 inch or less at a hundred consistently doesn't usually have bedding pobs or fouled barrel grooves.try a 160 gameking or speer for comparrison.guns are a law unto themselves.-anyone who says they would never get a bad group on an off day at longer range is having a lend of themselves .-good luck

 

[hntfsh]

Easy way to check your twist.Take your cleaning rod put a brush on make mark on the rod with a marker where it enters the barrel,then put another mark on it at least a foot up from last mark.Push the rod down the barrel,watch the rod when the mark makes a r4evolution,stop mark the rod again at the muzzle.Pull out rod and measure the marks thats your twist.I had a stabilizing problem with the old barnes x 175 gr in 7mmrem mag.many moons ago.They would key hole(the bullet wobbles during flightwhen it hits the target it leaves a keyhole)It wouldn't group at 100yrds for nothing.I changed weight problem solved.Your problem though sounds different,try other bullets as other suggest.Your scope and mount ok?1/2'' groups at 100yrds ,at 200yrds should be 1-2''groups.Another question is it pilot error,are you expierenced shooter over 100yrds(sorry have to ask)does it shoot factory ammo of the same weight,the same way.Lastly once you exhausted all possibilties ,take to er to a gunsmith