Petersen case capacity

[stagpanther]

Yes I'm lazy--I just bought a couple hundred Petersen cases in 6 creedmoor--does anyone have any idea how it's internal capacity compares with say Lapua's (+,-, or about the same)?

[T. O'Heir]

Their site is incomplete(the 'More info' button gives a 404 error), but you could ask 'em.
https://www.petersoncartridge.com/contact/

[hounddawg]

I used Peterson and Lapua with a previous .260 Remington barrel, there was no noticeable difference with regards to velocity or accuracy when using the same powder charge and bullet

[stagpanther]

It's always a bit of a mystery to me why case manufacturers don't list at least H2O capacity.

I used Peterson and Lapua with a previous .260 Remington barrel, there was no noticeable difference with regards to velocity or accuracy when using the same powder charge and bullet

Either similar capacity--or a great load.

[Bart B.]

Originally Posted by stagpanther

It's always a bit of a mystery to me why case manufacturers don't list at least H2O capacity.

The manufacturers have no control of the case condition, dimensions and methods used when customers measure them. There is no industry standard established.

Primer makers have been asked to show pictures of each type with several amounts of flattening with the peak pressures listed in 2,000 psi increments.

[hounddawg]

It's always a bit of a mystery to me why case manufacturers don't list at least H2O capacity.

probably because unless your are already well over maximum safe load or are capable of shooting .3 groups at 1000 yards you will never notice the difference

[Don Fischer]

I would think that you get ten different case's from ten different manufacturer's all the same cartridge and while there may be some difference it won't be much and certainly not enough to worry about. Start low and work your way up! Wouldn't it be something if two different brands of 308 win had a difference of 5 grs capacity! If that happened, one might be a 308 and the other won't be!

[Bart B.]

Originally Posted by Don Fischer

Wouldn't it be something if two different brands of 308 win had a difference of 5 grs capacity! If that happened, one might be a 308 and the other won't be!

Why not?

[Unclenick]

Yep. Tula 300 WM cases have a case water overflow capacity of around 87.5 grains H2O. Norma 300 WM cases have a case water overflow capacity of around 95.5 grains H2O. 8 grains different. What makes them both 300 WM is the external size and shape of the cases.

Incidentally, a relative newcomer, Atlas Development Group (ADG), claims its cases are very consistent in interior volume. See the first product review on this page. They are low capacity cases to increase metal for durabiity. AT 54 grains H2O it is more like some foreign 7.62 I've seen. I've measured as much as 59 grains capacity in some Winchester I have (15 years old). So that's a 6-grain spread.

[stagpanther]

ADG's are next on my list to try out--I've always been a "hard core Lapua" guy.

[hounddawg]

I bought 200 of the Alpha brass in 6CM and have found it to be is every bit as good as Lapua and Peterson. My match cases used to be 100% Lapua but I try to buy American when there is a good option

[stagpanther]

Agree.

I bought 200 of the Alpha brass in 6CM and have found it to be is every bit as good as Lapua and Peterson. My match cases used to be 100% Lapua but I try to buy American when there is a good option

So what's your best 6 creed load? I've returned to 105 vld's driven by 4350 as my best.

[hounddawg]

37.5 gns H4350 behind a 107 SMK and Federal blue box primers gives me .6 - .7 MOA 15 to 20 shot groups out to 800. Savage 12 action in a F class factory stock with a Criterion 28 inch barrel


https://thefiringline.com/forums/att...5&d=1548183714


https://thefiringline.com/forums/att...6&d=1548184161

[stagpanther]

Nice--I'm using 40.5 (large capacity Starline) and 39 (smaller capacity Lapua) 4350 with the 105 vlds out of a McGowen AR barrel. Can't really get that close to the lands due to magazine restrictions, the vlds seem to like a "long jump" anyway.

[stagpanther]

I just loaded up a few test cartridges using the Petersen brass--right off the bat I can say it's the most beautifully finished brass I've ever seen; probably helps a lot by being shipped in a regular ammo case with separate cells for each case.

[hounddawg]

These are for a single shot and no where close to magazine length. Next time at the range I need to load up a few and retest that load. Those were shot when the barrel still had less than 100 rounds. I am at 500 now. I am hoping the SD's dropped a bit. I did not have a lot of luck in matches with that load, thinking about pulling that barrel and putting a 6BR or 6 Dasher on it

[stagpanther]

I did some water fill tests--surprisingly I was coming up with 50.1 +/-; I was expecting less.

I am hoping the SD's dropped a bit. I did not have a lot of luck in matches with that load, thinking about pulling that barrel and putting a 6BR or 6 Dasher on it

It's interesting you mention this--I just finished testing some 108 vld loads using RL 23; very mediocre results until just for the heck of it I significantly increased the jump to lands using Hornady's recommended COL and the groups magically tightened up and this seemed to be repeated with most loads regardless of charge weight.

[stagpanther]

BTW hounddawg--have you done much with RL 23 in your 6CR? 4350 is pretty good when I find the right nodes--but RL 23 takes it to whole 'nother level in my 22" barrel.

[hounddawg]

Nope Stag sure have not. I am going to try and tweak that 37.5 load to see if I can get the numbers down but with the short barrel life I am not inclined to tweak it much. It's a very tight shooter out to 300 but the ES on this load sucks at 600 and 800 with a lot of vertical and odd flyers in the groups. I like the round though, I will put a 6CM barrel on another rifle this fall and move back to .260 Rem on my long range gun.

[stagpanther]

Nope Stag sure have not. I am going to try and tweak that 37.5 load to see if I can get the numbers down but with the short barrel life I am not inclined to tweak it much. It's a very tight shooter out to 300 but the ES on this load sucks at 600 and 800 with a lot of vertical and odd flyers in the groups. I like the round though, I will put a 6CM barrel on another rifle this fall and move back to .260 Rem on my long range gun.

I can't get out to much past 100yds where I shoot now, so my results may not be indicative of what you could get in your gun--especially since you're loading longer BUT not loading more powder from what I can see.

In the past few days I've tested multiple loads with the 108 eld using RL23, and generally get an over-all group of around .5 to .6 MOA at 100; but have in the past few days repeated several times where 3 of the 5 shots would go through almost the same impact hole. My technique sucks and I shoot off a wobbly table, so I think better results could be had. It's a nuance thing; but the RL23 seems to feel "smoother" with less of a snappy recoil than 4350; which has a "bite" kinda like varget IMO.

[stagpanther]

Yes--I'm talking about powder like it's wine.