Fire Forming 6.5x284 to .284

[AWLEAPHART]

Hello everyone,
When shooting virgin brass my .284 seems to shoot about 3.5 to 4.0 Inches higher @ 500 yards then formed brass. Does anyone else noticed this.
Now it's not as accurate as my fire formed brass.

 

[TonyR]

Hello everyone,
When shooting virgin brass my .284 seems to shoot about 3.5 to 4.0 Inches higher @ 500 yards then formed brass. Does anyone else noticed this.
Now it's not as accurate as my fire formed brass.

I've seen these differences when shooting brass for the first time even if it isn't a wildcat where the dimensions are going to change a lot. But, I think you can look at it as just another tuning variable.

I fireformed the first 500 pieces of brass form my Shehane with bullets, not COW or whatever and I didn't want to waste all of those components and my only barrel at the time so I worked up a very nice load with N165 that gave great vertical at about 2800 fps. I then shot many of these fireforming rounds in 600 yard matches and was very happy with the results. The velocity would have been fine for 1000 yards with the 180VLDs but the runout after neckturning was unacceptable for that distance so I only used them at shorter distances.
It takes about 1.5 grains of powder for the fireformed brass to get the same velocity as the fireforming loads so the "give" in the case does require some energy and I think this is what you observe with new brass that is probably way smaller than your chamber, just to a much smaller degree than my Shehane cases.
The concentricity isssue is real in any event with freshly turned cases unless they have been carefully sorted for uneven neck walls before you turn them. They start out concentric on the outside but end up concentric on the inside when they are neck turned but I find that they will shoot themselves straight on the first firing if I anneal them after I turn the necks.

 

[AWLEAPHART]

Thanks TONYR, for the info.
I neck size them up and then turn the necks. I just turn a small amount off to try to true them up.

 

[TonyR]

Thanks TONYR, for the info.
I neck size them up and then turn the necks. I just turn a small amount off to try to true them up.

I also size the 6.5X284 Lapua up to 7mm. I anneal because I believe that stretching the brass that much hardens it and the hardness increases the springback. RonAKA recently posted about the properties of brass and how little stretching it takes to work harden it.

I also inside neck ream to remove the donut before I turn the necks. I had Wilson make me an inside neck reamer the same diameter as the pilot on the neck turner. Makes very even necks.

 

[AWLEAPHART]

I have never got into the inside neck reamer thing. I just never found a lot of info on it. But I do believe it’s a good thing because I have always felt that the inside of the necks are somewhat wavy looking.
JHARDY told me do run a 7mm mandrel inside the necks with flitz to smooth them up.

 

[TonyR]

I have never got into the inside neck reamer thing. I just never found a lot of info on it. But I do believe it’s a good thing because I have always felt that the inside of the necks are somewhat wavy looking.
JHARDY told me do run a 7mm mandrel inside the necks with flitz to smooth them up.

Exactly right. Jim is a very knowledgable guy and was one of the first to compete with the Shehane. You have to be careful when you enlarge the necks because the new neck includes some of the thicker brass that was shoulder in the 6.5 case. Some cases will be worse than others, but you have to get it out of these or your neck turner pilot will not go all the way in unless it is too loose. The K&M carbide pilots have an end cutter than will plow through the donut but it doesn't touch the little longitudinal ridges that you can see inside the neck after you have expanded it.

The Wilson inside neck reamers work in place of the case trimmer cutter and are fitted so they follow the line of your case neck. The will take off the ridges and the donut. You order by size through Sinclair. Measure the diameter of your neck turner pilot and order that exact size to the ten thousandth. You need a micrometer that reads to 0.0001 to do this. As long as you use the expander mandrel that is matched to you turner mandrel, you will end up with a nice snug fit on the turner pilot after you ream the inside of the neck.

I just do it after I have expanded the necks while I'm trimming the cases to length. Just pull out the cutter and replace it with the reamer. You don't have to move the case at all if your trimmer is set up correctly. I use a ball mic to measure my case walls and the measurements varied depending on where I measured around the neck before I started using the inside neck reamer. Now they measure the same all arounds.

I do polish the inside of the necks with 0000 steel wool on an old cleaning brush before I load the cases. I've heard of the Flitz method and I should give it a try.

 

[AWLEAPHART]

So you only ream the inside. No outside neck turning?
Anthony

 

[TonyR]

I ream the inside first then neck turn the outside. The reamer does not thin the neck. It just removed bumps and the donut. Warner Tool will "NeckTurn" your brass on a lathe making the inside diameter concentric with the outside diameter and thinning the neck walls to whatever thickness you need.

 

[AWLEAPHART]

Thanks Tonyr.
I fully understand now.

 

[TonyR]

Thanks Tonyr.
I fully understand now.

No problem. I am an engineer, among other things, and didn't do very well in English composition.

 

[Jeffvn]

+1 on Alan Warner and his lathe for neck turning. I had a chance to talk to Alan in depth one day about what he does in prepping tight-neck brass, and its a fairly detailed process involving expanding with a mandrel, inside reaming, plus turning on the lathe. Only problem with paying him to do that for my brass is I'm capacity limited to only 2 kidneys and would have to sell one to get 1,000 pieces of brass worked up by Alan. I'm not saying it isn't worth it, I'm ceratin it would be, its just that I can't aford it (too many other demands on that cash flow these days).

I will offer this nugget of information, I had Alan "form" several hundred pieces of 338 LM brass for me on my 338LM Improved, using his fluid dynamic processing, and it was amazingly well done. I shipped him new cases with spent primers installed and he sent me new brass that was formed to my custom chamber and no gun powder was used at all. I annealed it and its super. Saved me a ton of time, bullets, and barrel wear on a new cartridge.