Caution with Peterson 6.5 Creedmoor LRP brass

[William Vogel]

Just put together a rifle using a SAAMI reamer 6.5 Creedmoor. Using some older Hornady brass everything is fine. Having 100 new Peterson brass, I began first firing. I was having some strange ES and hard bolt lift with several rounds through the lot although the loads were not supposed to be close to pressure limits and most velocity readings were in line with the load. Seated outside diameter of brass was .295, kinda tight! After doing some checking, the fired brass measured .296 and I couldn’t slip a .265 pin gauge in the neck. A .264 gauge had drag, didn’t try a bullet. The neck thickness measured around .0155 with a ball micrometer. I built a mandrel on my lathe for .2665 and expanded the brass over it and turned the neck thickness down to .014. Prepped all the brass and now it’s .292 loaded and fired necks again measure .296. ES and velocity now have stabilized and the new load is shooting about 1/2 MOA at 700 yards and about 1/4 MOA at 100. Load is 45.2 grains of VV N555 with CCI 200 Sierra 130 SMK/CN at 2.923 coal. Velocity is 2945-2958 with nice round primers. It’s supposed to be about 54000 psi. I used a throater to increase the freebore for heavier bullets. I’ve also got a Wyatts extended mag box. Kauger action and X-Caliber barrel.

Just take a close look at your Peterson brass before you get close to trouble. I don’t want anyone to take it for granted like I started to do with new brass and a “stock” chamber. Tight is good but must proceed with caution.

 

[round]

So, others should be experiencing the same issues if your using a saami spec reamer , correct ?

 

[603Country]

A few years ago I had a new barrel put on my 223. The gunsmith had put a tight match chamber in the barrel, which I didn’t ask for. I could not get my new Lapua brass reloads to chamber. Necks that are too thick are not something we usually look for. Took me a while to figure out the problem.

 

[William Vogel]

So, others should be experiencing the same issues if your using a saami spec reamer , correct ?

It’s a possibility that the neck thickness of the brass could be the same as mine, so yes. The chamber IS going to have the same dimensions IF the reamer is new or slightly tighter if it’s been used several times for chambering barrels.

 

[RGRobinett]

So, others should be experiencing the same issues if your using a saami spec reamer , correct ?

When Petersen began making the 6.5 Creedmoor brass, to accommodate SAAMI chambers without turning, they made thin walled neck, and a "Fatnecks" version which require turning to fit SAAMI Spec chambers. They did this intentionally.
Upon purchasing a set of various caliber Creedmoor reamers for a PAL, yours truly, obtained the standard neck for him and a 500 box of the Fatnecks for myself. The note I put in the carton indicates that the un-turned Fatnecks brass, with a 0.2641" Dia. bullet seated, measure 0.2961" across the bullet heel. It pays to measure stuff. RG

 

[dellet]

Honestly it’s more of a design problem. When you look at SAAMI neck dimensions. Maximum cartridge is .295”, minimum chamber is .296”. Add in maximum bullet diameter of .2644”. It’s a recipe for this type of problem.

If you’re counting on about 10 different manufacturers (you have to count not only the people who make the finished product, but also the tool and die makers) to be able to to keep 3 different products within .00033”, playing the zero clearance game is not very smart in a mass produced product that operates at 60,000 psi.

Also in the mix is a tapered neck in the chamber, brass pushing max length and diameter is more likely to pinch a bullet.

Then again any machine shop I have ever dealt with has made it clear, that the final check before and after assembly is the responsibility of the assembler.