I hear 2 different schools of thought on this. One is to use a reduced load, which I assume is to save barrel wear and throat errosion. The other method I hear is to used a stiff charge with a heavy bullet to get a more precise fire formed case. Which is the more preferred method? If I go with the reduced load, can I properly break in a new barrel with this method? Thanks

I've had good success with a light charge (starting load for the standard caliber) of fast burning powder, and the bullet seated to touch the lands. I've also used factory ammo. Both seem to give a complete fireform. As for barrel break in, the theory is the bullet travelling down the bore will knock down the burrs and imperfections. Velocity should not matter. As to barrel break in, it has recently been dismissed as a waste of time by some of the more knowledgable such as John Barness and Charlie Sisk on 24hourcampfire.com.

280_ACKLEY

I subscribe to the barrel break in proceedure that Sinclair International puts forth. I don't think you can make a bad barrel better by breaking it in, however I think you can make a good barrel perform better by following the Sinclair proceedure.

Rusty
We band of brothers!

I use a good quality load which is correct for the parent case and simply ignore the fact that the chamber has been "improved" until I get enough formed brass to work with. Normally 200 pieces of brass get me going.

This way I am able to shoot the rifle and enjoy it with no problem or loss of usable barrel life.

I shoot the 35 Whelen AI, and I use .357 pistol bullets with a medium load of IMR 4064.

I use this particular load just because it is inexpensive, and I can practice my off-hand shooting with iron sights.

The cases thus formed will then take my standard (stout) load of 55 grains of IMR 4064 with a 250 grain Swift A-frame bullet.

Garrett

For the .375 AI, I use a near full load for the non-improved case -- i.e., the standard .375 H&H -- with the bullet seated into the lands. It works fine, and produces a case that headspaces on the shoulder rather than the belt. Probably gilding the lily a bit in a .375 hunting rifle, but a little better accuracy never hurt a hunting rifle.

When I fireform brass for Ackley cartridges, I want my brass to last. That means making sure that the brass that expands to conform to the larger chamber at the shoulder flows from the neck/shoulder area, not the case body.

That's why I seat my bullet firmly into the lands for fireforming. Some of the additional pressure from starting the bullet into the lands will be expended forming the case, but not all of it. I want a good fireform (no Weatherby-like shoulders), but I don't want loose primer pockets. I use a medium dose of a fast burning powder designed for the parent cartridge.

Another method involves more work for yourself and the brass, but is actually better. The firing pin shoves the case forward with far more force than most people realize. This method involves necking up to the next caliber with a tapered expander and then necking back down in small increments until the bolt closes on the case with a slight crush fit. The case can't get any more centered in the chamber than that, and you know where the extra brass comes from. This is the only way to fireform for pushed shoulder cases like the JRS cartridges. Anneal the necks after fireforming and you're set.

For fireforming .375 H&H to .375 Weatherby I used 235 grain Speer bullets and a max load of IMR-4350 for the 300 grain Sierra right off the IMR website. I spray some Breakfree CLP on a paper towel and wipe the case body up to the shoulder. Chamber and fire, they come out beautiful.

When I fireform cases, I typically use a regular load of a medium burning powder and have the bullet jammed into the lands. Here's why.

1-I have seen fireformed cases end up a little on the short side in the headspace department. First cause is case movement from the firing pin blow. Seating the bullet into the lands will help prevent this. You can tell by looking at your fired primer and if it protrudes any, the case is short after forming.

2-You need a relatively stiff load to stretch the case backwards after the firing pin hits the primer and to form it well at the shoulder. I use a near max load (max, less a couple of grains for a standard load caliber case) as determined by guess and by golly. That allowance for a load would depend on the case capacity: more for bigger cartridges, less for small--say, about 2.5%-3% overall. I have a place that I can shoot at my house, it's not fancy, but I can aim the rifle into a backstop and test the load for pressure one at a time and make adjustments before I load up a whole bunch and head for the range.

3-Typically, I will use a relatively heavy, round-nosed bullet as it is easier to get to the lands and stop it there.

Hope that helps, Geo.

tlp335---

ALWAYS load UP with improved cases. If you're worried about barrel wear fireform cases with inert filler and pistol powder.... NO bullet.

The danger is a load that doesn't have enough energy to set the proper headspace. It's NOT the firing pin that drives the case forward.... It's the action of the primer against the floor of the pocket that drives cases forward before being blown back against the bolt face and out against the walls of the chamber.

If you see a "fireformed" case with a protruding primer FLATTEN THAT CASE WITH A HAMMER SO IT **CAN'T** BE USED!! It has excess headspace and a max load or a little chamber oil can ruin your whole life.

I'm MUCH more likely to leak a primer when fireforming than any other time. I like them HOT.....but I don't shoot bullets. I shoot grits.

Jack,
what would be a good load to form some 30/338 Lapua Imp cases? The headspace will be off the shoulder but the neck length is increasing so I'd like to form them "well" with Bullseye and oatmeal or something to iron them out first to do my neck turning on a straight neck with no indent at the neck/shoulder jucture.

My forming leaves the case smaller in diameter at the base of the neck from running the shoulder down the 30 cal and it's a .335" nk, so I need to turn them before loading bullets...

Case capacity is about 119gr water.

Thanks for any recommendation.

Brent---

I wouldn't use a triple-based powder in that big of a case. Unique or many of the similar burning rate shotgun powders are much easier and safer to work with.

I've heard various formulas for figuring how much of what to fireform with, but what I do is guess low and try and go up until the case is well formed.

Nineteen grains of Unique in an '06 case with just enough tissue paper to hold the powder in the case and then filled with grits and capped with a scoop of candle wax fired (at cedar moths or dragon flies) will completely and sharply form a Whelen case......and peel the wings off the game at ten feet.

I have several pounds of old Alcan 5 and 7 and several other similar powders that I use. 'The bigger the case the slower the powder' is the rough "rule" I go by.

Thanks Jack.

>It's the action of the primer against the floor of the pocket that drives cases forward before being blown back against the bolt face and out against the walls of the chamber.<

No, the firing pin drives both forward --stopped by the shoulder--, the primer backs up from pressure of ignition, and the case eventually goes rearward back over the primer. If the pressure is sufficient, the case is stopped by the bolt face. If the pressure is insufficient, the brass does not stretch all the way backwards and a small primer protrusion is visible on the fired primer. That is why this dimension needs to be checked after the first fireforming. I typically jam the bullet into the lands, so as to limit the initial forward movement.

Geo.

Perfect explanation. Tis true, the primer contacting the floor of the pocket and the case moving forward are just "reactions" to the firing pin action. A light lube keeps the web stretching from taking place, but thrust on the bolt is at it's greatest if using heavier loads to form brass with lube.

How can the firing pin drive the case forward if the headspace is properly set in the first place?

Unfortunately, proper headspace per SAAMI doesn't mean a crush fit on NEW brass. Tolerances exist because of differences in chamber sizes, due to new vs. worn out reamers, or good or bad chamber reaming jobs at the factory.

I've seen more problems with belted magnums stretching excessively after only one firing than with anything else. Sometimes a reloaded belted magnum will suffer case head separation on it's first reload because of the initial stretching that occurred during fireforming with the factory ammo in a factory chamber. Of course, this can be avoided by proper handloading for the first fireform, rather than using factory loaded ammo.

Most case head separations I've seen could have eliminated by better handloading technique. A friend of mine has had more case head separations with his .300 WinMag than anyone on this planet. Why? Mostly brain damage. I don't know how else to explain it. He loads too hot and always pushes the shoulder back on fireformed factory loaded ammo. By now, he has set his lugs back enouogh that he truly has a headspace problem with the rifle. Go figure.

[ 07-14-2003, 05:24: Message edited by: SST ]