6mm .236" Or .237"

T

Tclaunch

New member
I bought a Krieger blank out of the classifieds here, and it was never discussed about the bore size. The selling smith says he ordered the wrong twist was the reason for the sale. Well it came in today and is a .236" bore.

My question is, are any here that prefer the .236" over the .237". I got a feeling I`m not going to keep this barrel.
 
What is the twist, and what were you going to use it for?
 
My Theory

Tclaunch said:
I bought a Krieger blank out of the classifieds here, and it was never discussed about the bore size. The selling smith says he ordered the wrong twist was the reason for the sale. Well it came in today and is a .236" bore.

My question is, are any here that prefer the .236" over the .237". I got a feeling I`m not going to keep this barrel.
Click to expand...

If I were you, I would keep that barrel and use it if the twist rate is correct for your intended purpose. Although I have had good results from both Krieger and Bartlein barrels in 6mm with .237 bores, I have been wanting to try the .236. My reason is as follows;

Harold Vaughn proved that bullet core stripping is much more prevalent than many would believe. If your bullet cores were on the borderline of stripping due to traces of lube in the jackets, on the cores, or for whatever reason, a .236 bore would result in the jacket getting a stronger grip on the core during initial spin up reducing the possibility of core stripping, which has been found to be very detrimental to accuracy. Some bullets appear to be perfect in every way, yet they won't shoot worth a darn. I believe this is often the reason.

If I'm not mistaken, a Kreiger or Bartlein barrel that is cut rifled will have the same groove diameter whether it is a .236 or .237 bore. Smaller bore diameter means deeper lands, which MAY result in a tighter grip on the core. Can't prove it but in theory, it makes sense. Anyone else?? Comments?

Gene Beggs
 
Harold Vaughn reference????

Gene,

What is your opinion of Vaughn book. I have read it and tried to understand most of it. The few people I know in the BR world believe it is junk. It is their knowledge in it? I liked the chapter on exterior ballistics. It made sense to me.

tiny
 
It is an 8.5" twist, and will be chambered in a 6 Dasher on a BAT model B.

I spoke with a shooting buddy and Krieger about the .236" and may just keep it.

I`d still love to hear shooters input on this subject.
 
tiny68 said:
Gene,

What is your opinion of Vaughn book. I have read it and tried to understand most of it. The few people I know in the BR world believe it is junk. It is their knowledge in it? I liked the chapter on exterior ballistics. It made sense to me.

tiny
Click to expand...

Tiny, after the first time I read Vaughn's book, "Rifle Accuracy Facts" I came within an inch of throwing it in the trash because it conflicted with so much of what I thought I knew and all the formulas, equations and computer generated stuff went right over my head. But,,, something told me,

"Now wait a minute Beggs, consider who this man is and what he has done; do you actually think you know more than him? Is there any chance that maybe, just maybe he's right and you're wrong?" :eek: :confused:

So I placed the book on my night stand and began carefully reading it again. About that time I was honored to meet Dr Jack Jackson, the editor of the book and a close friend of Harold Vaughn. Jack introduced me to Harold and I was honored to visit with them at Harold's home in ABQ New Mexico.

Thanks to the patience and understanding of these two gentlemen I now have a far better understanding of extreme rifle accuracy especially regarding barrel vibration, exterior ballistics, and the effects of wind on airborne projectiles. Actually, I found that I knew very little and was badly mistaken about many things. So in answer to your question, "What do I think about Vaughn's book?"

IT'S PRICELESS!

Later,

Gene Beggs
 
I've got five Kriegers with .236" bores - one 7.5 & four 8-twists. The four 8-twists are all chambered for a .274" no-turn neck Dasher; the 7.5-twist is a 6x47 Lapua. The only .237" bore I have is an 8-twist Bartlein, also in 6x47 Lapua. All four of the Dashers are excellent shooters at 600-1000yds.

The Bartlein 6x47 handles Berger & DTAC 115s very well at velocities of 2990-3000fps. The 7.5-twist Krieger is on a BAT 3L and has only 50rds. through it to date. It shoots DTAC 115s into little clusters at 600, but Berger 115s are showing some vertical stringing. I haven't had the time or decent enough weather to experiment with seating depth with the Bergers - hopefully, that's all it'll take to eliminate the vertical. I worked up to 2960fps with both 115s, and that appears to be max in the .236"/7.5-twist Krieger.

I had both Bartlein .237"/7.8-twist & Krieger .236"/7.5-twist blanks in stock when I barreled the BAT 3L; making the choice between them was the hardest part of the whole rifle project. As good as the Krieger shoots with DTAC 115s, I'm still curious as to whether the Bartlein would've done as well, but perhaps produced a little more velocity than the .236" Krieger.
 
Well, this is very comforting to see some positive input over the .236" bore.

My smith is a very sucessful point blank smith, and as I learned yesterday speaking with Krieger,

a .237" is a natural choice for light weight bullets.

He had always ordered .237" and when this one came in at .236" I was concerned.

I will save this barrel till I can shoot my 6/47`s a few more outings at 600.
 
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