? on 6.5 saum build

[horse killer]

I pulled the trigger on a 6.5 saum build after I received hornady brass from GAP.
My questions are for shooting 140 Berger vld what twist is the best . I will be getting a bartlein barrel. Also what reamer should I get . I do not neck turn on any of the rounds I shoot now but am willing to start if it will make a difference. The rifle will be used for hunting.
Thanks for any information

 

[Predator 22]

I would use a 8 twist barrel and a no turn reamer. For a hunting rifle you will not see a difference between a no turn neck and a turned one in my opinion. Gap uses a 8.7 twist barrel, there thought is to use the slowest twist that will stabilize the bullet to gain a little speed. I will error on the safe side and have the twist that will fully stabilize the bullet no matter the condition even if it costs me a few fps.

 

[Sendero_Man]

8 twist will also build pressure faster.

both mine are 8.7 twist. Shot at elevations from 2650 to 10,900 with the 140 bullets.

no issues.

 

[lilharcher]

I'm building one right now too and posed some of these same questions to my smith (GAP). I went with the 8.7 twist, but you can also go to Berger's website and use their twist calculator to optimize twist based on your conditions (elevation and temp). Some are now saying a gain twist may be best (ie - starting at 8.7 and gaining to 8.2 for example). Like mentioned by Sendero though, you should be good in most situations with 8.7 twist.

As for reamer, if you will only be using the new Hornady Brass, I highly suggest the neck turn reamer at .296.......hornady brass is ~.261.

 

[horse killer]

Thank you for the replies. One question will the Hornady brass need to be turned to fit in the .296 reamer.

 

[jrsolocam]

Thank you for the replies. One question will the Hornady brass need to be turned to fit in the .296 reamer.

Over on spinershide they have some threads with literally thousands of posts on this subject . It's worth looking at.

 

[RockyMtnMT]

Neck turning brass depends on the reamer used. Tight neck or not.

I would not recommend no slower than 8" twist. Even the factory rifles are 8" twist. You want to be able to shoot the bullets of the future then go 8" or faster. We are working on a bullet designed for a 7" twist.

Steve

 

[Wind Gypsy]

Thank you for the replies. One question will the Hornady brass need to be turned to fit in the .296 reamer.

No. See the post above yours, loaded hornady necks are around .291".

Either gap reamer will work for 140 vlds. The .120 fb can be a bit long for JLKs and to a lesser extent hybrids if you want to chase lands but is better for most other 140 class bullets.

I'd get a .296 neck (and I did) because its perfect for 4S brass and you'd still need to turn necks with a .298 chamber if forming from 7 or 300 saum anyway.

 

[Sendero_Man]

Neck turning brass depends on the reamer used. Tight neck or not.

I would not recommend no slower than 8" twist. Even the factory rifles are 8" twist. You want to be able to shoot the bullets of the future then go 8" or faster. We are working on a bullet designed for a 7" twist.

Steve

The 6.5 4S was designed by GAP around an 8.7 twist barrel... For a reason.

long barrel life and low pressures.

Some are using an 8-8.2 twist, but they build pressure faster and will have shorter barrel life.

There are no "factory rifles" chambered in this round. All are custom shop rifles, GAP or other builders.

 

[RockyMtnMT]

The 6.5 4S was designed by GAP around an 8.7 twist barrel... For a reason.

long barrel life and low pressures.

Some are using an 8-8.2 twist, but they build pressure faster and will have shorter barrel life.

There are no "factory rifles" chambered in this round. All are custom shop rifles, GAP or other builders.

I guess it depends on how long a bullet you want to be able to shoot. Regardless of the cartridge, the twist will determine stability capability. The slow twist will run short bullets very well. I am sure it will work great for it's intended purpose.

Steve

 

[Sendero_Man]

It runs ever 130 and 140 bullet made incredible ....

I have two rifles in 6.5 SAUM. I shot the prototype and have been around them since designed.

Highly recommend them if you want a wind cheating laser beam

 

[horse killer]

Thank you for all the replies. I have decided to go with the 8.7 twist after looking at the Berger twist calculation chart it will work at the altitude I shoot at . Also I am going to go with the .296 reamer. The build will consist of a Defiance Deviant action Manners EH1 stock jewel trigger PTG BDL bottom metal bartlin 3b barrel Mussel muzzle break. Only thing that I need to decide on is what scope to mount on this

 

[Wind Gypsy]

Sounds like some good choices!

 

[Sendero_Man]

Thank you for all the replies. I have decided to go with the 8.7 twist after looking at the Berger twist calculation chart it will work at the altitude I shoot at . Also I am going to go with the .296 reamer. The build will consist of a Defiance Deviant action Manners EH1 stock jewel trigger PTG BDL bottom metal bartlin 3b barrel Mussel muzzle break. Only thing that I need to decide on is what scope to mount on this

sounds like a light weight hunting rig...

look hard at the NF 2.5-10x42 Compact

Incredible scope, lighter weight, great reticles, rock solid turrets, ease of use, zero stop, etc, etc, etc.