Resizing 5.56 brass

[golfer]

Is .007 too much to size brass down for a m4 rifle. I need to size my brass down to 1.454 [using a Hornady headspace guage] to fit in my m4. My son has an m4 and has me to reload for his rifle but there will be approx. .007 difference between my sized brass and his headspace. Is .007 too much headspace.
I can reset my sizing die for him, I am just being somewhat lazy and don't want to do that unless necessary.
Thanks for looking and best wishes.

[rcoodyar15]

Is .007 too much to size brass down for a m4 rifle. I need to size my brass down to 1.454 [using a Hornady headspace guage] to fit in my m4. My son has an m4 and has me to reload for his rifle but there will be approx. .007 difference between my sized brass and his headspace. Is .007 too much headspace.
I can reset my sizing die for him, I am just being somewhat lazy and don't want to do that unless necessary.
Thanks for looking and best wishes.

.003 to .005 is the recommended shoulder bump for and AR15. You are saying after sizing with your die your son's ammo will have a .007 shoulder bump?

If you aren't going for precision all it will do is shorten you brass life.

[golfer]

rcoodyar: Thanks much, I had been reading .005 in some places and .007 in a few others. Sounds like I should not consider the same for both rifles. I will just make him to the resizing, LOL.

[bigedp51]

golfer

Using your Hornady gauge, how long is a case fired from your AR15 and how long is a fired case from your sons AR15.

I'm loading for three AR15 rifles and there is less than .002 difference between all fired cases.

If your cases have .007 difference in their fired length then as a wild ass guess I would say one of your rifles is at or near the maximum length Field gauge.


http://i122.photobucket.com/albums/o254/bigedp51/headspace-b_zps7601219a.jpg

Below a Colt Field gauge at 1.4736

http://i122.photobucket.com/albums/o254/bigedp51/headspacegauge006_zps3cdabdf4.jpg

And below in my adjusted and calibrated Hornady headspace gauge.

http://i122.photobucket.com/albums/o254/bigedp51/headspacegauge_zps14d3b71f.jpg

If you loosen the set screw between red and silver sections and place a feeler gauge between the two sections you can adjust the Hornady gauge to read very close to actual case headspace length. All you then need to do is shoot the same ammo in both your AR15 rifles and measure these fired cases. I think if you have .007 difference you have a headspace problem "OR" you used cases with different spring back rates to take your measurements. Meaning a newer case with softer brass at the shoulder and a case reloaded several times with harder brass at the shoulder and effecting the brass springback.

Also depending on the gas system and how much the rifle is over gassed a fired case can "grow" longer than the chamber when fired. This is because the bolt can be moving to the rear while chamber pressure is still in the barrel. And this causes the case shoulder to move forward past its fired length when the bolt was locked close.

I would use new factory loaded .223/5.56 cases and fire several in each rifle to come up with a average case length for each rifle. To check my two AR15 rifles and my sons AR15 rifle I fired 3 each M193 cartridges in each rifle. And as stated before there was less than .002 between these three rifles, I then took the shortest case reading and added .003 shoulder bump for all my reloads for all three rifles.

[rjacobs]

I have my full length die on my 556 prep tool head set off of a piece of Federal XM193. I measured 10 factory pieces and they were all basically the same(within .005 to .01) so I set my sizing die to that. I load 556 for like 8 different rifles so for me, sizing to a known factory spec(federal XM193) works even though its not ideal for any gun, it runs in all of them. 1.455-1.457 is what the 10 pieces of Federal XM193 I measured ran in, so pretty good tolerance.

So your die, setup to 1.454 is close enough to what factory 556 is. I wouldnt change a thing and run with it personally.


Now my precision gun, yea I have its own sizing die setup for it only to bump 004.

[golfer]

biged: thanks for the reply. My Daniel Defense rifle measures 1.458 and my sons [can't remember the maker, maybe Conos or something like that] measures 1.461. I measured at least a dozen fired brass in each gun. He was using Wolf ammo and I was using a Chinese brand we got our brass from.
I loaded up 5 rounds for myself with 25 cfe223 sized to 1.454 and fired them in my rifle. No signs of over pressure. I did the same with my son measuring 1.458 which he fired successfully.
The more I look at the numbers, it appears there is .004 between our rifles, not .007.
Measuring head space is new to me but I assume I did it correctly. I found I had to rotate the empty shell in the measuring device to get the lowest measurement.
I'm not sure I understand the reasoning behind using the feeler guage.
rjacobs: Kinda what I thought relative to factory ammo.
By the way, I kept sizing each shell down until the bolt would close fairly easly over it while in the chamber.
Thanks you guys for your help, I certainly appreciate it.

[bigedp51]

I'm not sure I understand the reasoning behind using the feeler guage.


Technically the Hornady gauge is a "comparator gauge" and my gauge would read .009 more than my Field headspace gauge. And by adjusting the gauge using feeler gauges to lengthen the red and silver sections of the gauge it now measures actual headspace. Meaning closer to actual chamber headspace, I did this because I was loading for three AR15 rifles and wanted to know how close the three AR15 rifles were in "actual" headspace. (without counting on my fingers) :D

The GO gauge is 1,464 and new unfired Federal M193 cartridges were 1.462 and my fired cases were 1.467

Below a fired case

http://i122.photobucket.com/albums/o254/bigedp51/headspacegauge005_zps20685e73.jpg

Below the same case after .003 shoulder bump.

http://i122.photobucket.com/albums/o254/bigedp51/headspacegauge005_zps20685e73.jpg

Below a new unfired Federal M193 cartridge.

http://i122.photobucket.com/albums/o254/bigedp51/headspacegauge002_zpscc227fb8.jpg

In the photos above there is a .009 "air gap" between the red and silver sections and there is less than .001 error in reading actual headspace.
All three of the AR15s I was loading for were less than a year old and had very little ammo fired in them. And I just wanted to know how close the headspace was on all three rifles at initial barrel setup/indexing.

[golfer]

biged: You gave me an aha moment. If I understand correctly the .009 represents the difference between the head space guage and the Hornady gauge. That gives you a reference between the shoulder location of the Hornady gauge and the head space guage.
I don't have a head space guage yet but that sounds very useful.
Without the headspace gauge, are you saying there is really no way to apply the Hornady measurements to more than rifle?

[Bret]

I found I had to rotate the empty shell in the measuring device to get the lowest measurement.
This is completely normal. Just watch out for soft brass and quick ejection which might create a burr on the case head.


Without the headspace gauge, are you saying there is really no way to apply the Hornady measurements to more than rifle?
You can compare them to each other with the Hornady gauge and that's what matters more than their absolute headspace measurements.

If it makes you feel any better, I have a Sterling AR-180 that headspaces about 0.010" longer than my AR-15's. I do keep the reloads for it separate, but the cases for all my AR-15's get sized the same.

[golfer]

Bret: Thanks very much for the followup, great information for me to work with.

[bigedp51]

golfer

There is a second method to find the exact length of your chamber using a new or full length resized case and a spent fired primer.

1. Measure the new or FL sized case and write it down.

http://i122.photobucket.com/albums/o254/bigedp51/303gauge_zpsb1e333a7.jpg

Now just using your fingers start the spent fired primer into the primer pocket.

http://i122.photobucket.com/albums/o254/bigedp51/303primer_zpsae8fdb45.jpg

http://i122.photobucket.com/albums/o254/bigedp51/303primera_zps612343f9.jpg

Now chamber this case and slowly close the bolt letting the bolt face seat the primer. Remove the case and measure the case again, base of primer to the case mouth and write it down. Now subtract the first case measurement from the second and this is your head clearance.

http://i122.photobucket.com/albums/o254/bigedp51/HEADCLEARANCE-a_zps1a9a1011.jpg

With this case in the "calibrated" Hornady case gauge you have the exact chamber length, and on one of you resized cases the head clearance will also be the amount of shoulder bump.

With a rimed case if you add the rim thickness to your head clearance reading you will also have your exact headspace reading without the Hornady gauge.
(its the cheap bastards headspace gauge)

http://i122.photobucket.com/albums/o254/bigedp51/hedspace-b_zpsce06e3e4.gif

Also as Bret stated above adjusting the Hornady gauge is not necessary, "BUT" I wanted to know the actual headspace of three AR15 rifles and how close the barrels index to each other. Meaning I didn't want comparative figures with these three rifles, I wanted actual headspace values.

[golfer]

biged: That last one is great as I don't need to buy anything to do it. I will give it a try. Actually, I have 2 sons which makes 3 rifles for me as well, LOL. I will give it a go.