Peterson vs Lapua 6BR Neck Thickness.

[jackieschmidt]

I just received 150 Peterson 6BR cases.

This is the difference in the smallest part of the neck thickness as compared to a Lapua 6BR.

The Lapua, (bought this year), only shows an average .0003 variation in the wall thickness at the neck, while the Peterson is showing an average .0008. taking into consideration the wall thickness, the Lapua is about .0005 thicker at the neck.

I also converted 12 Peterson cases to 30BR using my “blow out” method. To achieve the desired .0098 neck thickness to use in my .330 neck chamber, they all exhibited a little “shadow”, as the necks get thinner when blowing them out as opposed to necking them up in the normal fashion.

I am going to shoot them Sunday.
View attachment 1585870

 

[ScottVA]

Interesting...but that watermelon looks great!

 

[jackieschmidt]

I fireformed 15 of the Peterson 6BR brass today to convert it to 6BRA.

I will head to Tomball tomorrow to shoot them, seeing how they compare to Lapua.

This of course is a 1-12 barrel shooting 32 grns N135 behind a Barts 80 grn Dominator.

 

[bozo699]

Well it’s Sunday,….. how did they do compared to your Lapua?… oh wait it’s only 11:24 a:m your still at the match. Let us know this evening inquiring minds want to know
Wayne

 

[jackieschmidt]

Just got home from the range, just before the rain hit.

I worked with the Peterson using several combinations, finally, (before the rain hit), found the sweat spot.

My load of 32.0 grins of N135 shot ok, but not good enough. After messing around, I switched over to H4895. I had to drop the load from 33.5 grns that shoots great in the Lapua down a full grain, to 31.5. I also had to go down .002 on the neck bushing because of the difference in the case wall thickness. Keep in mind, this is a no neck turn .272 neck in the chamber.

An indication of the difference in the necks of the Lapua and the Peterson is the micrometer measurement of the loaded round at the base of the 80 gen Barts Dominator bullet. We are looking at a full .002 inch.

But just before the rain hit I managed to shoot two groups with the load I developed. The velocity with the 31.5 grns of H4895 was an average 3300 fps, .002 neck tension, about .010 into the lands.

The Peterson Brass will shoot, even with the what appears to be a lot of neck clearance. I don’t know why Peterson chose to make it that much thinner than Lapua,

Anyway, in the morning, we will go and set up at 200 yards.

Here are the actual micrometer measurements over the loaded round, the Peterson, then the Lapua, and the two 100 yard 5 shot groups I managed to shoot with the Peterson before the rain.

 

[Kracken McGraw]

The five shot target with the Peterson brass is wonderful.

 

[gunsandgunsmithing]

That'll get it done. I'm not shooting my 30's as much these days and wonder how it holds up to pressure in the small 6's. I know you load mostly upper window so would like your feedback on that when/if you ever do it. 6ppc/6BR/6Grendel data. I hope it holds up well. Wondered for years why an American brass maker hadn't stepped up and made brass as good as Lapua.

 

[Clancy]

@jackieschmidt every lot of peterson is a little different neck diameter. There’s a link on their website where you can look at each lot and then call around and find a batch that’s .266,.267,.269, whatever.

Good shooting!

 

[USMCDOC]

@jackieschmidt every lot of peterson is a little different neck diameter. There’s a link on their website where you can look at each lot and then call around and find a batch that’s .266,.267,.269, whatever.

Good shooting!

that's good to know

 

[jackieschmidt]

that's good to know

Has Petersen released any info on why they can’t lock into a standard dimension and maintain it.

If they are going to go heads up against Lapua in the Competition Market, that being all of the Disciplines that use the 6BR as a parent case, they have to do better.

 

[USMCDOC]

Has Petersen released any info on why they can’t lock into a standard dimension and maintain it.

If they are going to go heads up against Lapua in the Competition Market, that being all of the Disciplines that use the 6BR as a parent case, they have to do better.

Jackie, you're asking the wrong person for that info.. i'm just a plebe with all of this stuff

 

[Dimner]

@jackieschmidt every lot of peterson is a little different neck diameter. There’s a link on their website where you can look at each lot and then call around and find a batch that’s .266,.267,.269, whatever.

Good shooting!

Is it like that on all their brass? Or just 6br?

 

[Straightshooter1]

Is it like that on all their brass? Or just 6br?

Neck wall thickness often varies from one lot to another no matter what brand you're looking at.

Here's an example from Peterson Cartridge company's own data:

 

[boltfluter]

I just received 150 Peterson 6BR cases.

This is the difference in the smallest part of the neck thickness as compared to a Lapua 6BR.

The Lapua, (bought this year), only shows an average .0003 variation in the wall thickness at the neck, while the Peterson is showing an average .0008. taking into consideration the wall thickness, the Lapua is about .0005 thicker at the neck.

I also converted 12 Peterson cases to 30BR using my “blow out” method. To achieve the desired .0098 neck thickness to use in my .330 neck chamber, they all exhibited a little “shadow”, as the necks get thinner when blowing them out as opposed to necking them up in the normal fashion.

I am going to shoot them Sunday.
View attachment 1585867View attachment 1585868View attachment 1585869View attachment 1585870

Jackie,
What is your method for blowing out to 30BR? Some very nice shooting on your part!
Paul

 

[Clancy]

Is it like that on all their brass? Or just 6br?

Everything they make.

And yes, Lapua and alpha vary lot to lot as well, but peterson does publish the info on their website.

 

[jackieschmidt]

I shot at 200 yards today, and the word for the day was WIND. 10 to 20 mph ebbing and flowing.

The weather really tuned, instead of 100 degrees, it stayed in the high 80’s with an overcast which eventually turned into a rain shower.

The tune I used yesterday was not working. So I spent quite a bit of time just getting the rifle right, or as right as I could tell in the conditions.

I finally jacked it up to 33.7 grns of H4895. The weather was turning so I got three groups on paper, taking my time and reading the flags to the best of my abilities. Velocity is an average 3430 fps with the 80 grn BARTs Dominator. Then it started drizzling rain. After that, I retrieved the wet targets and hung a score target and shot the target posted.

The rifle is performing. I kept the three 5 shot groups at 1/2” or a little under which in all honesty is about all you can expect from me at 200 yards in this kind of wind. I think this upper end load is at the limits of the Peterson Brass, as by the time I got to the score target, extraction was becoming a little difficult. In all, I probably have around 15 firings on these cases.

The only complaint I have about the Peterson is the overly thin necks. Most no turn chambers are .272/.273. That means this loaded round has .006 clearance in my .272 chamber. In the World of Benchrest, that’s pretty excessive.

 

[jackieschmidt]

Jackie,
What is your method for blowing out to 30BR? Some very nice shooting on your part!
Paul

If you notice, the neck on my 30BR is longer than usual, as the way I make cases retains much of the original 6BR 1.560 overall length.

I took a 6BR barrel and ran a .330 chucking reamer into the neck. When I fire a loaded 6BR round in this chamber, what comes out is a fully formed Factory 30BR case, if such an animal existed, ready for neck turning.
The cases come out around 1.545. I had a reamer ground with an over all chamber length of 1.550.

I have been shooting this chamber for quite some time.

Here is what a Lapua 6BR case looks like after firing in this chamber and neck turning.

 

[Silo1616]

If you notice, the neck on my 30BR is longer than usual, as the way I make cases retains much of the original 6BR 1.560 overall length.

I took a 6BR barrel and ran a .330 chucking reamer into the neck. When I fire a loaded 6BR round in this chamber, what comes out is a fully formed Factory 30BR case, if such an animal existed, ready for neck turning.
The cases come out around 1.545. I had a reamer ground with an over all chamber length of 1.550.

I have been shooting this chamber for quite some time.

Here is what a Lapua 6BR case looks like after firing in this chamber and neck turning.View attachment 1586981

I'm surprised the neck will seal with that much clearance.

 

[boltfluter]

If you notice, the neck on my 30BR is longer than usual, as the way I make cases retains much of the original 6BR 1.560 overall length.

I took a 6BR barrel and ran a .330 chucking reamer into the neck. When I fire a loaded 6BR round in this chamber, what comes out is a fully formed Factory 30BR case, if such an animal existed, ready for neck turning.
The cases come out around 1.545. I had a reamer ground with an over all chamber length of 1.550.

I have been shooting this chamber for quite some time.

Here is what a Lapua 6BR case looks like after firing in this chamber and neck turning.View attachment 1586981

That certainly is a good looking case! Very nice.