fun with fire forming

[yorketransport]

I've got a thread about forming 338/375 Ruger brass from 8x68s case over on LRH which goes along with Jasent's thread about his 338/375 that he just finished and I though a couple folks here might think it was interesting too.

Here's the results from the forming I got done today. All cases were trimmed to 2.600" and formed using a false shoulder sized for a crush fit in the chamber. Everything was fired from a 338/375 Ruger Savage Striker.


Brass dimensions are an average of 10 samples of each brand. Norma and RWS case are capacities after a single fireform load.

Hornady 375 Ruger brass
Empty case weight: 262.2gr
H20 capactiy: 100.1

Norma 8x68s
Load: 22.8gr Trailboss, 277gr MTAC, CCI BR2
Empty case weight: 282.6gr
H20 capacity: 95.5
Length after forming: 2.585"


RWS 8x68s
Load: 21.8gr Trailboss, 307gr Hammer Hunter, CCI BR2
Empty case weight: 274.6gr
H20 capacity: 96.4gr
Length after forming 2.582"


I love the fact that I recovered a couple of the bullets in the dirt bank. Muzzle velocities are around 1900 fps and the bullets obviously didn't stabilize. The interesting part was that they grouped fairly well considering they're un-stable and the group was shot by my 16 year old daughter at 100 yards.

[jasnt]

Tagging along. Mynorma brass won’t be here till I’m headed to bear camp so it will be a few weeks before I can form

[luteai]

When I fireformed 30-06 AI brass I used bullseye with cornmeal to fill the case and a soap plug for a bullet. Would that work for your project? Cheap and could shoot in my garage no need to travel.

[jasnt]

Yes it would but you may not get a full fire form.  Plus if you have components you won’t use it’s a way to use those. Plus you still get to plink while fire forming

[yorketransport]

When I fireformed 30-06 AI brass I used bullseye with cornmeal to fill the case and a soap plug for a bullet. Would that work for your project? Cheap and could shoot in my garage no need to travel.

I’ve formed a lot of cases using the cream of wheat method over the years. It works pretty well but you have to clean the carbon and burnt cereal out of the barrel every 5-10 shots. There’s also some trial and error in finding the right powder charge that will give a good form without being over pressure and ruining the brass.

Using Trailboss and a bullet to form the cases takes all the guess work out of finding a load. All you do is either form a false shoulder to headspace off of or load the bullet long enough to jam into the rifling to hold the case hard against the bolt face. To figure out the powder charge all you do is fill the case with powder to the base of the bullet and weigh the charge. Trailboss burns very clean and is designed to generate pressure over a long curve compared to other powders. This makes it great for forming brass without the high pressures caused by using fast burning powders.

I always have a collection of odds and ends bullets that I can’t use for anything else, so this is a good use for them. The bullets I used for this project either shot poorly in all my guns (the 277 MTAC) or are samples of an early prototype design (the 307 Hammer Hunter). I may try using cast bullets too just to see how they work.

[jasnt]

Tracking says I’ll have my brass today

[yorketransport]

Tracking says I’ll have my brass today

Let the tedious forming process begin!!!!!

[jasnt]

Every time I order anything my mail man just leaves a pink slip. Won’t leave anything in my mail box.    gf will pick it up today

[jasnt]

Haven’t gotten around to forming yet but I do have few cases ready to form

[yorketransport]

I've had a chance to work with both the RWS and Norma 8x68s brass now and have 3 full power firings on each brand of brass. So far I can't tell a difference between the two. With a fully formed RWS case I use 78.3gr of H4350 with a 230gr ELD-x to get 2855 fps from the 18" barrel. With a Norma case I use 78.4gr H4350 to get 2850 fps with the same bullet. Between the two, I'd probably just go with the Norma brass since it's so cheap right now.

[jasnt]

I got 100 ct of Norma and 100 of Hornady.  Are you trimming before or after forming false shoulder?

[jasnt]

Got 25 cases about ready to fire form

[Crunchy]

I finally got 200 pieces of Norma brass.  Plan to fire form soon as rifle gets done.  Question for you though.  Do you run them through FL sizing die first, or just primer, powder and seat bullet?  My Norma brass neck seems tight enough to just seat a bullet without having to run through a die first.

[yorketransport]

As long as the necks look nice and round, I’d just load and shoot. You could run an expander through the necks to clean them up if they look a little rough.

[jasnt]

I neck up to 375 then down to 338 forming a false shoulder. In my chamber that will fit but I may need to trim it a bit.  Dosent look like the neck goes in the free bore to me.  Little more testing to be done before I decide