Who actually uses the SAAMI reamer on AR barrels?

[jurassic]

Enjoy your barrel. I won't hate on you because you picked something different from me.

Love it! I think most on here feel this way.

[Drifter]

I ended up here and looking on three other forums about information about this cartridge. I ended up here thinking it'd have the most information but I quickly began to realize that this forum generally is a fan of a specific chamber design over it just being a cartridge. It was the performance numbers of a bullet and cartridge combo that attracted me to this round not a throat design. Then due to the massive amount of bickering on both sides of the issue I almost said "screw the grendel"...

The thread linked below is from nearly three years ago. The link will take you to page 3, where I think you'll find the discussion to be relevant and familiar.

http://www.65grendel.com/forum/showthread.php?2848-6.5-css/page3

I posted that link not only for your potential benefit, but also for those of us that have been around longer. I'll just leave it at that...

[LRRPF52]

Someone sent me this link a while ago and found it interesting enough to share:

http://bulletin.accurateshooter.com/2015/01/murdicas-masterpiece-just-about-as-good-as-it-gets/

Radical New Reamer Design from PT&G
Lou used a new chamber reamer from Pacific Tool & Gauge (PT&G) with special geometry in the leade/throat section. Called a “Bore Rider” (or sometimes “bore-runner”), this new reamer design cuts a staged, variable taper in the leade/throat area that is quite different than the taper in a typical throat. It’s a little hard to explain, so we’ve included the 6 PPC Bore Rider reamer print below.

Thanks for that blast from the past Drifter. It reminded me of some of the milestones along the way in this legacy. One important thing I had forgotten about was how so many barrel makers were dealing with demand, while not having any reamer or chamber prints for 6.5 Grendel even after SAAMI approval, which can be a long and painful process.

For example, the .458 SOCOM has been on the market now since 2001 and enjoys support from one of the biggest manufacturers in the AR15 industry (Rock River Arms), as well as one of the most well-respected custom shops (Wilson Combat). There still isn't SAAMI approval of the .458 SOCOM, yet it has been produced for a decade and a half, complete with its own share of reamer and chamber problems that have reared their heads for some customers.

The fact that the 6.5 Grendel went as early as it did through SAAMI submission and approval, and was a relatively pain-free experience once it was out of AA's hands, shows that it was very well designed and thoroughly tested.

I still think that many of the barrel makers are using other chamber designs because of the industry trend that existed before SAAMI approval, and the fact that most people go to PTG for reamers since they are fast.

A lot of customers in this generation are not known for patience, so that reflects in rifle builders.

[bwaites]

Am I looking at a compound throat from Dave Kiff? I'm not an expert on reading these, but that's what it looks like to me?

[LRRPF52]

Am I looking at a compound throat from Dave Kiff? I'm not an expert on reading these, but that's what it looks like to me?

Yup. See that .2435 and .2398 "staged, variable taper in the leade/throat area".....

That's a compound throat. From the article:

Radical New Reamer Design from PT&G
Experts should look at the leade angle(s), freebore, and throat dimensions. You may be surprised. Dave Kiff of PT&G says this Bore Rider design has worked successfully for other cartridge types/calibers as well. Apparently this design helps the bullet center up smoothly in the bore before the bullet engages “hard” in the rifling — or so we’ve been told.

The funny thing is that a compound throat doesn't work well in higher pressure chamberings because anything much over 55,000psi will plasma cut the shallow initial leade before the conventional one.

I wonder what other cartridge types/calibers they are referring to where this design has been so successful?

[bwaites]

Ain't that a kick in the pants? LOL