Peterson “long” 300 wm brass

[Chicken155]

Does anyone have any experience with the long 300 wm mag brass? It seems like a great idea. I was just wondering if anyone has used it? Thanks.

 

[Aviator]

I’ve been using it since it came out. Good stuff in my opinion.

 

[Chicken155]

Thank you.

 

[Jason Snyder]

I use it. I have about 4-5 loads on my first lot of cases.

 

[MThuntr]

I have been using it basically since it came out. I like it and you don't see case stretch right like you do with other belted brass. I'm only on like 3 loadings on the 100 I have been using right now so I think I still have a lot more loadings left. Set your dies up to do a shoulder bump versus a full length sizing.

 

[Chicken155]

I was going to size it so there is just a little resistance at the bottom of my bolt closure. Will that be okay? Also I purchased a Larry Willis magnum collet die.

 

[wind gypsy]

I was going to size it so there is just a little resistance at the bottom of my bolt closure. Will that be okay? Also I purchased a Larry Willis magnum collet die.

If doing that I'd expect occasional cases to have a lot of resistance (too much) on bolt closure but maybe other's sizing practices are more consistent than mine. I see no good reason to do such a thing and a handful of reasons to avoid it.

 

[MThuntr]

I was going to size it so there is just a little resistance at the bottom of my bolt closure. Will that be okay? Also I purchased a Larry Willis magnum collet die.

I've not used his dies. I've heard they work well with traditional sizing practices but I've not run into the belt bulge issue yet and a lot of that issue may be resolved by only sizing as minimal as possible. Most belted mag dies push that stretched brass back down because they headspace off the belt not the shoulder. If you use the Long brass you can headspace of the shoulder and there shouldn't be the bulge though it could be an issue with brass you shoot a lot.

If you don't have one get a headspace comparator setup from your preferred brand and measure your oncefired brass and bump as necessary.

 

[Chicken155]

Okay. I appreciate it. How much shoulder bump do you use?

 

[MThuntr]

My oncefired brass gets about 0.002". That seems to be the "standard" you'll see on forums but it kind of depends on what works for you. Some prefer a little more to prevent any issues if you're hunting and your rifle gets dirty or some moisture gets between the brass and chamber.

 

[Andouille]

Here's a very long and descriptive thread about the long brass. I'm tempted to pick up 50 pieces which should last 10+ firings if I anneal and size minimally.

Peterson 300 WM - Std Length vs. Long - Initial Data & Impressions

Peterson 300 Win Mag brass - Standard Length vs. Long - Initial Data & Impressions Introduction This thread is being generated for a number of reasons, not the least of which is in relation to the comments and questions that have come up during the multiple active threads regarding the release...

www.longrangehunting.com

 

[Chicken155]

Thanks. I’ll check that out.

 

[wapitibob]

Smoke the shoulder on a fired case and chamber it, if it touched the chamber you'll see it in the soot on the brass. It might take two firings to get it fully grown. You can then bump it back .001 at a time, then use the smoke method to see where you need to be, to clear. I usually run .002 bump after the brass has grown. I also use the willis die on every piece of brass, after every firing.
As mentioned, get a comparator so you have some numbers.

To smoke the shoulder, run the brass shoulder thru a wax candle flame. The wax in the flame will add soot to the brass.

 

[wind gypsy]

RE Willis die - I had issues with Redding type s dies pushing a little ridge of brass in front of the belt to where headspace got tight there at the belt. The die is plenty tight at the base but because of that it caused chambering issues. Might have had something to do with a lousy chamber because that barrel kind of sucked all around. A Willis die every loading would have prevented that Norma brass from becoming useless after 3 firings though.