338 Norma Improved

[264MHC]

As long as you feel a notable resistance when chambering either factory ammo or handloads, there is no need to jam, but some people do it anyway as extra insurance. In my 264 MHC, improved 6.5x55, my chamber was cut for 156 Bergers but I fire formed with 140 RDFs that I found for .20 apiece. The RDFs jammed had very little bearing surface in the neck, but I knew this so I figured as long as I shot them when chambered it wouldn't be a problem. That is until the range went cold right as soon as I chambered a round, and I had to pull it out, resulting in powder dumping in my action, not fun. From then on, my fireform loads have been light touch, but still a crush fit on the brass, and I haven't seen any difference in formed brass. Hopefully my experience is helpful to you.

 

[Rhovee]

Lapua is .009 short and Peterson is .018 short of go guage. So a guy really needs to have brass in hand. Even then the Peterson is so short I had to grind a shell holder down

 

[Lonewolf74]

Thank you all for your help and advice! I get it clearly now, basically I just wanna make sure the cartridge in some way is held in place and not flopping around in the chamber.

I found some older Hornady round nose 250 grainiers on a shelf that I think would work good for forming and should have no problem getting them jammed cus there flat base and long bearing surface, and best part is there $30 for 100.

Anyone ever use H414 to fire form? I got some left over from another project and be great to use that up

 

[cjuve]

I fire form using Ramshot magnum or any other powder that has data available for the parent cartridge and bullet that I am shooting. H414 seems a little fast so finding data may be difficult. I would also be concerned about case fill ratios and getting consistent ignition. I am far from an expert on the subject so I am only relaying what has worked for me. There may be others that have more experience that would be able to help.

 

[Charlie Brown Jr.]

I started out wanting a 338 Norma Imp, then used the same reamer with a 338 Lapua go gauge, and 338 Lapua brass. I just gained a little more powder capacity. I had an old Rem 338 take off bbl. and chambered it for the Improved Lapua, then fire formed with 700 x and filled the case with kuinoa or cream of wheat, and saved my Brux bbl. for the real thing.. Still a work in progress, looking for the right scope. Pictured is 338 Lapua on left 338 L Imp and a 300 Norma on the R.. Good Luck..

 

[Lonewolf74]

Lapua is .009 short and Peterson is .018 short of go guage. So a guy really needs to have brass in hand. Even then the Peterson is so short I had to grind a shell holder down

Rhovee, why did you grind down the shell holder for the Peterson brass? Wouldn't the brass stretch out to your headspace after a firing or two?

Got me thinking I should buy a box of Lapua brass just in case I run into problems with the Peterson.

 

[Rhovee]

Since the Peterson was .018 short of go gauge, I had the chamber cut to the brass. You couldn't screw the die down enough to bump the shoulders back.

 

[Lonewolf74]

Rhovee, I understand what your saying.

I have one more question for you. What is the loaded neck diameter of your Lapua brass vs the Peterson? I want a no turn setup and am wondering if I should specify a little more clearance on the neck. It's currently specked at the standard .3705 which is .005 clearance with my Peterson brass, and .006 clearance with Norma brass. Just wondering if the Lapua brand has thicker necks yet?

 

[Rhovee]

It's .366. You'll be fine

 

[FEENIX]

Don't waste your money on a hydraulic forming die, I bought on for my 338 LAI. I measured the water grain capacity before and after- waste of time. Your best bet is to just fireform.

I have a positive experience with Whidden's hydraulic forming die on my .30 LARA.

From L-R:
1 - 8MM RM virgin brass
2 - After a couple of whacks off the hydraulic forming die
3 - After using re-sizing die
4 - Fireformed off the chamber

 

[waveslayer]

I have a positive experience with Whidden's hydraulic forming die on my .30 LARA.

View attachment 353525
From L-R:
1 - 8MM RM virgin brass
2 - After a couple of whacks off the hydraulic forming die
3 - After using re-sizing die
4 - Fireformed off the chamber

That's what my .338 Norma looks like. In fact here's pics of 3 shots from hydro formed and once fired. Not bad POI shift I'd say.

 

[Lonewolf74]

I have a positive experience with Whidden's hydraulic forming die on my .30 LARA.

View attachment 353525
From L-R:
1 - 8MM RM virgin brass
2 - After a couple of whacks off the hydraulic forming die
3 - After using re-sizing die
4 - Fireformed off the chamber

Feenix, just wondering do you have to size with a sizing die after forming with the hydraulic form die or could you load and shoot right from the hyd. form die if you wanted to?

 

[FEENIX]

Feenix, just wondering do you have to size with a sizing die after forming with the hydraulic form die or could you load and shoot right from the hyd. form die if you wanted to?

You can load and shoot after hydraulic forming die, just like you would after COW forming. However, "if" you have a sizing die for it. "I" would recommend running it through first. My hydraulic forming die was custom-built using my custom reamer's blueprint, and my sizing die was custom built with brass fire- formed off my rifles' chamber.

Hopefully, @waveslayer would chime in on his process too. Cheers!

Ed

ADDED: Check out #9 and 10 of your other thread >>>https://www.longrangehunting.com/threads/338-norma-mag-improved.291708/#post-2488399

 

[waveslayer]

I run mine throw my custom sizing die as well, after the hydro die. just to ensure proper neck tension is there. So far so good