Fireforming Loads More Accurate

Anyone else find this or have this problem, my fire forming loads are always more accurate than formed brass loads, not by a lot but still enough to piss me off after going through all that trouble to tool up. I even have a 243 barrel that was shooting fine, then I Ackley it same thing so all I end up doing is fireforming brass, I just can't seem to find the sweet spot whether it be coal or load. They do look cool Though.

From left to right 260, 260AI, 25-06, 25-06AI, 6MachIV, 6MachIV formed

http://i1290.photobucket.com/albums/...pstpoyrtii.jpg

Dean

Your fire forming loads are light and your regular loads are blistering fast. The bullets are mis-shaped from the near nuclear explosion behind them?

i had the same problem with the 260AI i played with....FFing loads where stupid accurate then the formed loads where accurate but not as no matter what i did...also at about 800 or so rounds the barrel was done...it was a set back barrel but i figured even if new it would of lasted about 1400 to 1700 rounds...at this point i decided the AI just wasnt worth all the hassles for 2 reasons...first being barrel life and second(and more important)i just wasnt seeing the claimed speeds unless i really started abusing brass at which point you have to ask yourself is it worth it.

Lots of things could cause it. That brass is never the same after the first firing. Most likely concentricity. Likely when you are resizing but bullet seating can add to the.problem. get you a concentricity gauge.

I am sure you have searched for that magic combination of bullet, powder charge and seating.depth.

scope eye

What type dies are you using to size your cases.

At the Whidden custom die website they say they get the least runout with standard non-bushing full length dies. I use the cheaper Forster full length dies with the high mounted floating expander that greatly reduces neck runout.

If you use a bushing die and reduce the neck diameter .005 or more you will induce neck runout. This is why they say to reduce the neck diameter in two steps when reducing the neck diameter .005 or more. A bushing die works best with a tight neck chamber with neck turned brass and standard SAAMI chambers allow the case neck to expand over .005.

I agree. The expander is the meanie when you size the neck that far.

I Full Length size every time due to necessity "Cases are Bloated" my FF loads are actually hotter than my formed loads, I think I just answered my own question, a formed 6MachIV will send a 105 Amax a 107 Sierra and 107 Berger over 4000Fps that is pretty surreal.

Dean

Quote:

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Originally Posted by Robinhood

I agree. The expander is the meanie when you size the neck that far.

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Expander diameter and the neck diameter of the die both play a part, and Forster will hone the neck diameter at your request. All resizing dies have variations and the expander is blamed when the neck of the chamber and the neck of the die work the brass the most. I bought a Forster .223 die with the intentions of having the neck honed but all that was needed was to polish the expander. This expander only expanded the case necks less than .002 and on some brands of brass it hardly touches the inside of the case neck.

Are Your Sizing Dies Overworking Your Rifle Brass?
http://www.massreloading.com/dies_ov...ing_brass.html

http://i122.photobucket.com/albums/o...psvgj7lnlt.jpg

FL Bushing Dies vs. Honed FL Dies
http://www.accurateshooter.com/techn...honed-fl-dies/

I don't like to pull an expander ball through to stretch the brass back to size for a random neck tension. All of my precision dies are full length sizers that I reamed and polished to the size I desire for the brass I use.

I will have to check the few things that were mentioned, I don't remember having this problem before, It is not my first AI. I am getting 3100 fps while FF with 140s in my 260AI.

Dean

Quote:

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Originally Posted by Robinhood

I don't like to pull an expander ball through to stretch the brass back to size for a random neck tension. All of my precision dies are full length sizers that I reamed and polished to the size I desire for the brass I use.

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Redding bushing dies come with a expander for people who do not turn their necks. Meaning you need the expander if you do not neck turn or else you are just pushing the neck defects to the inside of the case neck.

Below is a average Remington .223 case with .004 neck thickness variation and some of the cases had as much as .008 variation.

http://i122.photobucket.com/albums/o...ps079ece9b.jpg

http://i122.photobucket.com/albums/o...ps66bcfc13.jpg

If you do not use a expander with these type cases you will be pushing the bullet into a egg shopped hole. The most working stress on the case neck is when it is fired and expands to the neck diameter of the chamber. And case lube works wonders for the inside of the case neck and it will not "stretch" the neck or shoulder.

People who do not lube the inside of their case necks remind me of the Star Wars male Ewoks.

http://i122.photobucket.com/albums/o...psbvuxp9sf.jpg

My case necks never scream in pain or get stretched.

Because I polish or replace my expanders with carbide units. Below a RCBS expander before polishing that was replaced with a Lyman carbide expander.

http://i122.photobucket.com/albums/o...psb90ff6de.jpg

Lyman Carbide Expander/Decapping Rod Assembly for Lyman and Rcbs Dies 30 Caliber
https://www.amazon.com/Lyman-Carbide.../dp/B005I0KTXU

WOW I have a concentricity setups but never use it I guess I am going get busy.

Dean

Quote:

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Originally Posted by scope eye

WOW I have a concentricity setups but never use it I guess I am going get busy.

Dean

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Check the loaded rounds and sort them. Shoot the ones with less than 0.003 runout and see if your groups don't improve.

After sizing and Before loading check neck concentricity. Those two checks will tell you if you have a problem and if it is sizing or bullet seating or both.

Might even check a fired case to seek if the bore isn't concentric to the chamber.

Quote:

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Originally Posted by m12lrs

Check the loaded rounds and sort them. Shoot the ones with less than 0.003 runout and see if your groups don't improve.

After sizing and Before loading check neck concentricity. Those two checks will tell you if you have a problem and if it is sizing or bullet seating or both.

Might even check a fired case to seek if the bore isn't concentric to the chamber.

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So what would happen if after checking for concentricity, the case head was marked and all cartridges single fed
into the chamber the same way as compared to being fed without concern?
Is uniformity the issue, or perfection?

I went out to the range this morning and had a few experimental rounds with me, and it turns out I wasn't sending them fast enough "silly me" so 50gr+ of RL19 and 3200 fps + later Eureka. I did polish they expander and really lubed the inside of the necks. I really didn't any any case lube so I borrowed the KY from the nightstand. so now I am good to go.

Dean

Quote:

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Originally Posted by yobuck

So what would happen if after checking for concentricity, the case head was marked and all cartridges single fed
into the chamber the same way as compared to being fed without concern?
Is uniformity the issue, or perfection?

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I don't think it would help. Why don't you try it and get back to us

I have even tried the Hornady concentricity gauge and straightener. I feel it.effects.neck tension. Too much

For.me accurate loads 0.003 or.less the rest.are.plinkers