Fire Forming to harden case heads....do you?

[bigngreen]

On the first SS we built, which were the first, we had Rem brass and Norma, the Rem I retired just because I wanted to play with something else after 20+ firings. The Norma definitely does better if you punch it light the first round regardless of chambering. The newer ADG your gaining more just by finishing the final forming before starting to run at the higher nodes.
I've proof tested many of the first of the Sherman chamberings and I'm not much of a slacker in the pressure department and I've only lost a couple primer pockets and that was just me trying to see where the tip top was and what it showed up as. One was a poop barrel and I'm glad I was the first to fire it cause my standard test load cut loose, I had a bad feeling about that barrel as soon as I looked at the marking on the end!!

 

[Wedgy]

Didn't someone build shotgun adapter to fire COW rounds for fireforming (see picture)?
At the very least I would rechamber a Savage take off barrel and headspace it off one of your fired rounds and use that for fireforming. Wouldn't be a bad idea to have a rental FF barrel. I did something similar for a 4runner axle bearing puller I fabricated instead of buying the $450 tool. When someone needed it they would paypal me $200 and I would send them the tool, they would do the job and then would post that it is available and the next guy would send him $200 paypal and he would ship the tool to them. I have not seen it in 18 months and ~40 people have used it.

 

[parshal]

I built a fireforming "chamber" like the one pictured and used my $150 single shot to fire form for the 65SS. It's crazy how hot that barrel gets with just a little bit of titewad and COW.

 

[340PR]

Hadn't heard of this, but I am getting up to 20 firings out of my Norma and Lapua brass with pretty hot loads. I may lose a few cases toward the upper end of firings due to loose pockets. I normally start with enough brass (and other components) to shoot out a barrel, based on 15 loadings. IE. 200 cases X 15 loads= 3000 rounds, which is more than my barrels last. Works for me..

 

[WiscGunner]

Fire forming brass with light loads is always good for brass life as each rifle and brass lot is different and fire-forming gets consistency. Now when this is a new build/barrel the barrel needs to be copper seasoned to stabilize velocity increase load data won't mean much for the first 100-200 shots. My question is why would anyone want to work with a full power load or do load development from the get go? Or are people building these fancy wildcat rigs to shoot shotgun distance where accurate data is unnecessary?

 

[Redfoot Ranch]

Generally speaking, I fire-form and 'harden the case head' with a 90% load of QL max. This is usually accomplished with my cheaper, less desirable components with 50 pieces of new brass loaded at lands touch. I will seat deeper 4 pairs of loaded rounds in .009" increments OTL's - the final pair ending 36 thou off. I will shoot this first 10 acquiring a good avg MV and doing a coarse seating depth test. The remaining 40 rounds are seated deeper to the best shooting of the 5 depths and these may be shoot at fur or steel at a distance.

Interestingly, a pet load for my 6.5-284 with a 140 class bullet produces a high single digit ES/low single digit SD with new brass that I prepped and seasoned as explained above. I loaded 10 rounds of everything the same other than it was loaded into some once-fired brass I acquired in a trade. I had a hunch as easily as the primers seated that these would perform to my liking from a numbers standpoint, with an ES of 62 and an SD of 16.

To further some additional testing, tomorrow I am going to shoot 20 rounds in a side by side comparison with 10 cases of brass I prepped and that of this acquired fired brass at 4 targets. This will also show me on target what I believe I feel is a seating interference difference with 2 different neck lubes.

I think case hardening is worth it for longevity of brass life. I personally don't begin load development with this batch of brass until it's been fired this way.

My $.02

 

[Mikecr]

Now when this is a new build/barrel the barrel needs to be copper seasoned to stabilize velocity increase load data won't mean much for the first 100-200 shots. My question is why would anyone want to work with a full power load or do load development from the get go?

I'm sure most people desire to get up and running with their new rigs as fast as possible.
I spend the brunt of my time with cold bore development, and this can take weeks.
But hot bore development is first, and I don't like to spend a lot of time on that as it holds no practical application for me.

That said, I don't waste time with ANY powder development until the brass is fully fire formed and stable.
So I won't burn up my barrel FFing ~200 cases, as folks who don't get much brass life do. Instead I'll setup 50 best cases and run with that for the life of as many barrels as I can. Of course that doesn't happen without a plan.

The 'copper seasoning' does not apply to me as far as I've seen.
I clean my bores to white metal after every use. I break-in new barrels with 10 shots of Tubb's Final Finish.
There is no MV change from my barrels for their entire accurate barrel lives.
But then, I shot ~250 shots FFing 50 cases and developing a hot bore load. It could easily take another 50shts to tweak in a cold bore load.

I respect peoples thinking and discussion about brass hardening for long term gain. Good ideas

 

[Hugnot]

Waste of time - brass cartridge heads are work hardened at the time of manufacture. Exceeding certain pressure limits for any piece of brass will exceed the elastic limit for that particular piece of brass & will result in getting into a plastic state & enlarged primer pockets - we have all been there. Possibly there might be some industrial process to beat on the brass head exterior to decrease brass grain size and make for more work hardening.

An electron microscope, beam of electrons vs. light, could be used to anlayze the grain size as a measure of work hardening. This would determine when an optimuim degree of work hardening was obtained. Exceeding the elastic limit of the brass would make for enlarged primer pockets. The cost of the e microcsope would be about 4X the cost of a low end Razor scope. I would prefer to buy real good brass like Lapua and forget about DIY work hardening.

 

[lancetkenyon]

How many pieces of brass is that Lance?

1100.