Fire forming brass?

168bergersapper

168bergersapper

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Hello my fellow CGN'S, I have a question that I really hope someone can help me with. I have been reloading for sometime time now, mostly 308, 30-06 and now 300RUM. My question is- Does fire forming brass and only neck sizing rather then full length re-sizing make a huge difference in accuracy? does it depend on the rifle? should I be doing this to optimize performance of my loads? why is this practiced? Thank you friends for any input you may have to help?
 
When your brass is fire formed to your chamber there is less movment when the cartrige dicharges minimizing vibration making your gun more accurate. You should be able shoot some groups in brand new brass, then reload the same load into the fire formed brass and see the groups improve. The increase in accuracy from new brass to fire formed in my 7mm is pretty dramatic
 
Sometimes it helps, sometimes it doesn't seem to matter and sometimes it gets worse. Either way it won't take long to find out. Much depends on how straight and tight the chamber is in the first place, a horribly oversize factory chamber may benefit where a minimum or under Saami spec chamber may not.

I can usually size straighter cases in a full length die than a neck die, bushing style or not. Proving that that makes a difference has been somewhat harder. I did buy FL bushing dies to replace my Redding neck bushing dies and in at least a couple of instances ended up with small base FL bushing dies where neck dies used t0 live.

I suspect that if Id just spent the die money on good brass and more barrels Id have been farther ahead.
 
Bullet seating depth (with proper powder charge) will give you the best results for accuracy - typically seated into lands or just off. This is the biggest gain in accuracy I've seen (way better than seating to COAL and the minor differences between FL sizing & neck sizing - none of these even come close to seating depth for accuracy gains). See a load development test I did for friend's Palma, where you can clearly see the huge difference seating depth makes:

http://s1350.photobucket.com/user/seraphimarmoury/slideshow/PRECISION%20LOAD%20TESTS/Savage%20Palma%20308

That was with Lake City brass (many times fired from my rifle) FL sized, using CCI BR primers and my favourite powder - can't give away all my secrets here...but I'm a sponge always researching and try to learn from others experience, then tweak it to my own ;)

The problem with neck sizing only is that the cases continue to 'fireform' to your chamber ;) meaning after a few 'reloads' brass doesn't shrink back and chambering becomes tight - so this means full length sizing after every 5th or so neck size (sometimes not even this many before FL sizing). FL sizing also can be done wrong as you need to screw the die down far enough to make sure the shoulders get bumped enough (have you FL sized and couldn't chamber the brass...the case can actually INCREASE in length as the brass 'flows' if the die isn't down far enough to bump the shoulders).

Note: Some knowledgeable competitive shooters BR/F moved away from neck sizing, back to custom made FL sizing dies. Remember they also usually have custom FL dies, tight chambers, neck turn, neck tension kept to minimum (again part of custom die or high end dies) and don't use the expander ball (which can throw necks out of concentricity). Some more tweaks to accuracy, which will probably mean more to BR/F competitors. Again, bullet seating, then powder will give you the largest gains in accuracy, tweak it from there.
 
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Well, this is just MY opinion on this, take it how you will...

If you are a benchrest target shooter, where accuracy rules all, YES, fire-forming new cases may get you the accuracy you wish. Fire-forming means that the cases you use are perfectly fitted to YOUR gun's chamber, and that chamber only. There is absolutey no way that the next chamber made with the same reamer that yours was made with will be identical in all respects.

Why, you ask??

The answer is simple: metal wears. The steel reamer that makes the chamber of your particular gun will wear off some of the metal used to bore the chamber (this is why tool edges dull and need sharpening) for YOUR gun, and the next chamber made will not be the exact same as yours. A tool & die maker could explain this better, I'm sure, but what it really means is that no two chambers, even those made by the same tool, will have the exact same dimensions.

Hunters say "who gives a damn" and they're right. Hunters care only that the rifle shoots to where the sights are, so they can kill the target animal with one shot. They don't care about a millimeter of difference at 100 meters.

Benchrest shooters care only about how close the holes in the target are together. They use special dial cailpers to measure the groups they shoot in the target. Hunters just don't need (although it's nice to have for confidence in your rifle) that kind of accuracy.

IMO, if you're reloading your ammo for hunting, fire-forming your ammo isn't worth the trouble. If you're working on a wildcat, or benchrest target shooting, then fire-forming your ammo may be the way to go for ultimate accuracy.

It really depends on you and what you want to rifle and ammo to do.

YMMV
 
My take on it is this:

I'm a benchrest shooter mainly, so I fall into the accuracy rules all else category.

But that being said, I love neck sizing only as I don't have to lube my brass so right there its a huge time savings. Then if you factor in the fact that fireformed and necksized brass in my experience needs little to no trimming. The other night I decapped and necksized 250 .303 brithish rounds. Out of the 250 I had 4 that were too long.

The last reason I fireform and neck size is the less you work you brass the longer it will last.
 
Keep in mind that after a certain amount of firing, you will need to FL size too, so a FL die is Neck Sizer's best friend.
 
With a standard factory rifle and remchester brass I would full length resize with .001 to .002 shoulder bump.

This subject came up in another forum and a noted national shooter quoted his winning friends statement.

"I get my best accuracy when the case fits the chamber like a rat turd in a violin case"

Meaning this American Southerner full length resized all his cases. ;)
 
hopefully not hijacking this thread....where can one get a neck sizing die in Canada (for a decent price?) I have looked on the sponsors and found a redding die, but its pretty expensive. Any one know where I can get a RBCS version (f/ 30-06)?
 
Tinman204 said:
My take on it is this:

I'm a benchrest shooter mainly, so I fall into the accuracy rules all else category.

But that being said, I love neck sizing only as I don't have to lube my brass so right there its a huge time savings. Then if you factor in the fact that fireformed and necksized brass in my experience needs little to no trimming. The other night I decapped and necksized 250 .303 brithish rounds. Out of the 250 I had 4 that were too long.

The last reason I fireform and neck size is the less you work you brass the longer it will last.
Click to expand...

Best answer..........and if I may add there are more than a few neck sizers. The Lee Collet Die (neck sizer) is simple to use and produces very, very, very little runout. Of all the Lee tools...............I like this the best. Love it on .223, the little cases are hard to manipulate in my hands....no lube, no sizing......less to go wrong........brass lasts longer.
 
Akito said:
hopefully not hijacking this thread....where can one get a neck sizing die in Canada (for a decent price?) I have looked on the sponsors and found a redding die, but its pretty expensive. Any one know where I can get a RBCS version (f/ 30-06)?
Click to expand...

Don't know what is available in your neck-of-the-woods. Google Titan Reloading. A US based website. They ship to Canada. Prices are great. Use the absolute most economical USPS shipping rate. I ordered three neck sizer dies for $60 (total) and the shipping was $15.
 
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