Barrel configuration for a 7mm Rem saum

[Dave Z]

Like to know what works in 7mm SAUM 1:8.5 or 1:9 useing 180 going to shoot in Match Rifle F/Class can any one help

[Gadget]

Hi Dave
I use a 1:9 Benchmark for 175 smk's.
Gadget

[Cameron Mc]

I have 3 x 1-9.5" twist 7mm's.

All shoot 175smk's and Berger 180's without any problems.

Cameron

[AlanF]

Cameron,

I tend to look on your low velocity and 1:9.5 twist experience (and Marty too?) as pushing the limits of bullet stability. Its good to know that you don't have problems - it means my 1:9 is out of the danger area. I personally recommend 1:9 if people ask. I have a 1:8.5 on order, just to see how it goes. The 1:9 has the advantage that it is widely offered as a standard option - I presume not all barrel makers would supply a 1:9.5?

Alan

[Dave Z]

hi Alan, I do have a 1:8.5 MTU just waiting for reamer to get here. Some say 8.5 is to fast for the SAUM??

[Cameron Mc]

Cameron,

I tend to look on your low velocity and 1:9.5 twist experience (and Marty too?) as pushing the limits of bullet stability. Its good to know that you don't have problems - it means my 1:9 is out of the danger area. I personally recommend 1:9 if people ask. I have a 1:8.5 on order, just to see how it goes. The 1:9 has the advantage that it is widely offered as a standard option - I presume not all barrel makers would supply a 1:9.5?

Alan

Alan

The twist I use is probably not a good starting point as it may not work with all situations. I use Krieger barrels, these are cut rifled so alot easier to select twist rate.
I spoke to Brian Litz last year in Brisbane about this and his answer was the bullet makers recommened a faster twist than is usually required to cover themselves.
I have another 1-9.5" on order so hope it still works for me.

It's probably the quality Queensland air that makes things different
Plus 2 lug actions

[AlanF]

Dave,

As far as I know the main risk of having too much twist is that at high velocity you may get "blow-ups". You'll soon find out if that's happening! You may get a bit more coppering too I guess. I think you could easily get by with a 1:9 if you're intending to run 180s at 2900+. I bought the 1:8.5 just to cover the extremes e.g. sub 2750fps, sea level in the middle of a Victorian winter! But I'd go ahead with it - you'd have to be unlucky to get problems - if the bore has a good finish then you shouldn't get blow-ups, particularly with Bergers which now have thicker jackets.

Hope it all works out.

Alan

[ratshot]

mmmm another 7 saum in match rifle , ive been steering one for a few years now , it a 28 inch 9 twist 175 smk and 180 vld have also been useing it for 500 fly and 1000 yd BR. So Dave where are you and what is your closest MR range. cheers Paul D...

[Dave Z]

Paul my home range is lower light SA I am about 15min's away, I also shoot 284W. Cheers Dave

[Dave Z]

Thank's Alan & Cameron
I be shooting at lower light with the Bergers as soon I get it going I will post

[AlanF]

...It's probably the quality Queensland air that makes things different
Plus 2 lug actions

Sorry I missed your reply earlier Cameron.

I did notice quite a lot of hot air up there, particularly in the early stages of the teams event.

Alan

[Cameron Mc]

Thinking back when I decided to go with the slower twist in 7mm, the projectile quality and variety was not available like now.
So our idea was to spin the 175smk as least as possible to minimise error. Now we have much better projectiles so 1-8" to 1-9" should not be as big an issue.
We just have to hope we get quality barrels.

Cameron

[bruce moulds]

cameron,
i think you just nailed the reason zerb needs 7" twist.
he's using a barnard for god's sake.
keep safe,
bruce.

[johnk]

I did notice quite a lot of hot air up there, particularly in the early stages of the teams event.

Seemed to work OK in FS.

[MROFD]

Go for a 280AI Dave..........Any SUAM in a Storm.