Unstable 180 gr Bergers in 7mm Rem Mag

[Mikecr]

I agree with you Canadian Bushman. It's not a stability issue.

 

[bdpayne2000]

Environmentals were:

Wind 3 to 15 mph
Altitude 690 ft
Temp 63
Pressure 30.008
Humidity 50.8%

Pacnor swears it is a 1-9 twist and that the patch test can be off a bit. I specifically ordered a 1-9 to shoot 180's and told them that when I ordered. Called Berger and they didn't really have anything to offer other than they suspected twist.

I will shoot a few more to see how they do but unfortunately to go longer than 600 is not convienent or real close for me. I appreciate all the feedback and thoughts. It's very nice to have such a good bunch of folks to interact with and learn from. Brian.

 

[Dick Tinsley]

You're approaching some ultra-hot velocites for the 180's in a 7mm RemMag...

Have you checked your crown? Could have a nick in it, or could be off-center causing funky gas expulsion to kick the boattail around as it leaves the bore...

Also, your barrel could just simply not like the 180's. I've got a sporter barreled 7mm RM that has a 1:9 barrel that just doesn't like 180gr bullets...VLD's or Hybrids. But it slings the 168's into a 1/2-5/8" groups all day long.

But my old Sendero SF 7mmSTW with a 9.25" twist barrel, loves all 180's I've shot through it.

Sometimes barrels can be picky. You just have to figure out what your's likes and stick with it.

Got to agree! If everything else is falling in to place( your load,etc) like Muddrunner said, check your crown. Just my 2cts!

DT

 

[Canadian Bushman]

Environmentals were:

Wind 3 to 15 mph
Altitude 690 ft
Temp 63
Pressure 30.008
Humidity 50.8%

Pacnor swears it is a 1-9 twist and that the patch test can be off a bit. I specifically ordered a 1-9 to shoot 180's and told them that when I ordered. Called Berger and they didn't really have anything to offer other than they suspected twist.

I will shoot a few more to see how they do but unfortunately to go longer than 600 is not convienent or real close for me. I appreciate all the feedback and thoughts. It's very nice to have such a good bunch of folks to interact with and learn from. Brian.

I dont want to say its impossible for your twist to be the culprit, just that its highly unlikely with the info youve provided.

The first thing i would do is verify twist, which youve done, and the patch test isnt real accurate but it will give a you a good estimation. This eliminates the concern of getting a barrel with the completely wrong twist. I.E. a 1:12 instead of a 1:10.

Now that you know you have aprx. a 1:9.5, and that is sufficient to stabilize your chosen bullet.
The second would be to re do the shoot, and see if i could reproduce the same results.
If for no other reason than to appease me, try to group your shots a couple feet from the ground. Like i said earlier ive dialed the wrong elevation and bounced bullets onto steel sideways, and it looked like a stability issue until i noticed the scuffs on the ground 8-10ft in front of the target.

 

[cohunter14]

If for no other reason than to appease me, try to group your shots a couple feet from the ground. Like i said earlier ive dialed the wrong elevation and bounced bullets onto steel sideways, and it looked like a stability issue until i noticed the scuffs on the ground 8-10ft in front of the target.

This is my guess as well...I have mistakenly done that before too.

 

[bdpayne2000]

So I can't claim to be infallible either as I have made that mistake as well. I will reshoot next time I can at 750/800 which will probably be a couple months so it will be a while before an update.

Thanks, Brian.

 

[Mikecr]

No matter what caused em to whack a target sideways, if they were good at 600 they were stable at 750.
If they were unstable(enough to tumble) you'd know it by 20yds.

 

[blksno]

Shhhh.. Don't tell my 7RM that 2920 fps is ultra hot with 180s, because it might just start believing it and drop 200 fps.

Dido on that one...Mine are going 3100 from a 25" barrel out of a 8.5 twist.

 

[deadidarren]

Dido on that one...Mine are going 3100 from a 25" barrel out of a 8.5 twist.

me too, mine are at 2960 26" tube 1:9.25

 

[bdpayne2000]

OP update. Was at the range doing load development at 300 yards On a different gun but had the 7 with me and three rounds. Shot all three and they grouped right at 1" and none keyholed. I don't know yet but I think I agree with all who posted stable at 600 is stable at 750 and think given my setup that day the three sideways skipped off the ground. Was shooting prone down a gradual hill with bullseye only 18" tall, not at all inconceivable that I did that. Next time at my range when shooting 600 will confirm and then next time at my buddies range we will shoot elevated at a target higher off the ground. Thanks for the help so far, Brian.

FYI, Pacnor swears it is a 1-9 twist and I think I believe them and also believe I am the problem. They said the patch test is not a perfect way to measure twist as they do it with a lead plug. Just wanted to set the record straight as it relates to Pacnor.

 

[bdpayne2000]

Update from the OP. Shot at 800 and 1000 yesterday. At 800 once I found the steel 3 shot group 2 inches at 1000 3 shots 6 inche group. Every shot on the steel was a perfect splash. I am supremely confident that Canadian Bushman solved the mystery in that I skipped the three that were sideways off the ground. I will now attempt to find a couple hundred 180's. Thanks for all the help, Brian.

 

[Canadian Bushman]

Even a deaf dumb and blind hog trips over a root and falls on an acorn every so often. Good shooting and enjoy those 180 hybrids.

 

[deadidarren]

Even a deaf dumb and blind hog trips over a root and falls on an acorn every so often. Good shooting and enjoy those 180 hybrids.

HAHAHAHAHAHAHAHA i like that one

 

[chrishatley]

Good call Bushman, as I read through this thread I knew you were right on. Glad to see the OP has his problem solved. I've learned more from the guys on this site than anywhere else. Keep up the good work fellers'.