Almost ready to get back into the game, producing match grade .303 British ammunition

[milsurprifleman]

A while back I ran into money problems and had to sell off all of my reloading gear but as a result of skimming every dollar that passed through my hands, I am now able to start the process of producing my "match grade" .303 British ammunition.

At my door yesterday was a package containing 100 rounds of Prvi Partizan 180 grain soft point .303 British ammunition. I just got back from the hardware store where out of crazy luck I managed to find 100 of the perfect size O-rings which are now placed on each round.

As soon as this wind and rain breaks I will head out to the range and initiate step one of the process "Fire-forming". Its about damn time I get the ball rolling as I was getting the with-drawl symptoms of zero bench time.

:rockon:

[BattleBornArms]

what do you do with the o rings if I may ask?
What size primers does that brass take?

[milsurprifleman]

what do you do with the o rings if I may ask?
What size primers does that brass take?

O-rings, I'm not sure how it came about or whether is was a developed method for the Enfield rifles, the rimmed cartridge of in conjunction of them both.

The Enfield has a "generous chamber" and an entire different style of head-space which causes the fired shell to slide rearward which then creates a false shoulder. By placing and o-ring against the rim, when chambered the base of the round is tight against the bolt face leaving zero room for the "slide back". This in return gives you a positive shoulder and an exact copy of the rifles chamber.

The case is now fire-formed and is ready to be neck sized. Other than a great increase in accuracy, your brass life just doubled.

Privi Partizan uses standard large rifle primers.

[chili]

O-rings, I'm not sure how it came about or whether is was a developed method for the Enfield rifles, the rimmed cartridge of in conjunction of them both.

The Enfield has a "generous chamber" and an entire different style of head-space which causes the fired shell to slide rearward which then creates a false shoulder. By placing and o-ring against the rim, when chambered the base of the round is tight against the bolt face leaving zero room for the "slide back". This in return gives you a positive shoulder and an exact copy of the rifles chamber.

The case is now fire-formed and is ready to be neck sized. Other than a great increase in accuracy, your brass life just doubled.

Privi Partizan uses standard large rifle primers.

Very interesting. Learn something new every day.

[milsurprifleman]

Very interesting. Learn something new every day.

I remember when I first learned of this method, I was blown away.

[pigpen]

what size o-rings?

[BattleBornArms]

so, let me get this straight
a rubber O ring is meant to take up the slack on a rifle with excessive headspace by placing the cartridge firmly against the bolt head correct??

And if you have excessive headspace, this is supposed to keep the case from stretching too much correct?

can the rubber O ring prevent that much pressure from bulging the case and blowing out from excessive headspace??

I have had a few rounds blow up from excessive headspace. 1 blew a hard metal receiver and bulged a quality steel receiver - that little rubber O ring is supposed to prevent a case from rupturing because a firearm has too much headspace?

I would personally replace the bolt head on the Enfield until headspace was improved, and if that was not possible, then i would not recommend shooting that firearm. I have seen the effects of 7.62x54r (another rimmed caliber that headspaces on the rim the same as 303) in a Maxim barrel with too much headspace and i find it really hard to believe that the rubber O ring is going to help much.

Please explain to me if i'm not grasping the purpose behind the O ring

[bladeworks123]

Being on the verge of being an old fart, I know about this one. The rubber o ring is not used in firing the loaded cartridges. It is only used to fire form the case and stetch it out to match it to the headspace of the rifle on rifles that are long on headspace. The o ring is put around the case above the rim on a primed empty case. When you close the bolt on the case the o ring holds the case tight against the bolt head. When you fire form the case, it stretches the headspace of the case to match the headspace of the rifle, Then you neck size only when you reload the round. Unlike firing a loaded round that will stretch just above the rim in the web and separate, the fire forming only stretches the case at the front of the cartridge, thereby keeping from developing a thin spot above the rim at the web.
Keeps the cases from stretching above the head when you fire the round, extends the life of the brass, and prevents case separations in the loaded rounds.

[BattleBornArms]

That makes perfect sense now thanks for explaining it better

[bladeworks123]

what size o-rings?

There are three or four sizes that will work IIRC. But the idea is to get one that will roll on fairly snug up against the web side if the rim and be small enough in diameter to not stick up high enough to prevent the casing from fitting in the bolt head, so it depends on the size of the case you are dealing with.

This is actually an interesting thread becasue this process is used to solve a similar problem to what us DRB guys go through on .308 win.

Just like the Commercially produced USA .308 win cartridges, Commercial .303 british cartridge casings have thinner walls than their military counterparts, and the rifles are headspaced a little loose from the get go. So what happens with the .303 brit and commercial ammo is the same thing that happens with the CETMES and .308 win. Some of them will work, some wont. It's a grab bag depending on how tight the rifle headspacing is. The advantage for the DRB folks is that the .308 cases are always held tight against the bolt head. The CETME DRB action has no real headspacing, so when the bolt is locked the .308 cases is dangling a little bit in the chamber being held tight to the bolt head by the extractor. I found these old pics....not mine but they illustrate the theory....

26858

26859

Now notice the similarity to the problem with the .308 win in a 7.62 NATO chamber in these pics from my "book".

26860

Fire forming is a good method of "manufacturing brass" to fit a rifles chamber, especially for the .303 or any other rimed case that can't be found, if you can't get it any military surplus from anywhere where else. For us CETME and Hk guys it's easier to just find some ammo that will work, and it keeps the cream of wheat from plugging up the flash hider..:icon_biggrin:

[milsurprifleman]

Well done guys, I never was very good at going into detail. Ask my wife, she is always half way in the dark LOL.

I am one of those guys who never really needs to explain because I am always the one doing it.

Thanks for picking up my slack:wink:

[oldpaint0]

I am not so good at getting the point across either. I like this thread though. Fire forming brass and using old Lee handloaders for my bolt actions is fun and produces some very accurate shooting. Thank GOD for the old wildcatters.

[turbothis]

nifty