My old man was sizing a bunch of mixed headstamp brass and was coming up with .006” of variance across brands (.004 under sammi to .002 over). Individual brands stayed pretty close but the spread across all brands was that big. I’m trying to wrap my head around exactly why. Shot thru two different ARs, I believe all were once fired but can’t be sure. His take was to just get a set of comp shell holders and sort it. My take was to back the die off and find a middle ground, back off the powder a few tenths and make ammo. He’s not after precision but he’s particular about everything. But I’m just after Minute Of Asshole to about 300. This might be a real stupid question, but why would there be so much variance across brands? My best guess is a difference in hardness and spring back. I mean, the internal dimensions of the die didn’t change. His take is that it was because of variance in the case itself, thickness of the rim maybe? Any input? And how do you handle mixed head stamps?
- Thread starter Dot3
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How are you coming up with "(.004 under sammi to .002 over)" meaning what method are you using to measure.
You are not measuring anything near real "sammi" dimensions with a comparator.
You are not measuring anything near real "sammi" dimensions with a comparator.
Good point, although new lapua measures 0 on his gauge. Help me out with the name, but it’s a dial indicator screwed into the press down to the shell holder. Still doesn’t explain the .006” variance unless it’s tolerance in the comparator.
Which dimension are we talking about here? Are they long? Fat at the neck, datum line, shoulder, extractor cut? Where is this brass out of spec? We need more information?
Full disclosure, I haven’t touched any of it. I watched him pull the handle a couple times, but his comparator is measuring the length of the case base to shoulder. Haven’t measured any thicknesses or anything. The eye catching part was .006” variance across brands (length from base as it sat in the shell holder to a datum point on the shoulder). Could be some tolerance stacking on the tools in use, but within brands there was hardly no variance shown.
Is your old man indexing the casehead-shoulder datum based on brass already fired in the rifle(s)? If no, why not? For example, if fired brass from a given AR measures 1.559” the sizing die should be adjusted such that the brass measures 1.555”, so .004” shoulder bump.
Also the variance can be explained by any number of things, mixing different headstamps among them.
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If new lapua brass is zero on your comparator then measure a fired case from the rifle(s) you intend to reload for using the same comparator.
Now adjust your die so all cases fall between the two numbers and you should be fine.
So if the lapua brass is zero and your brass fired from your rifle is say .008 then all cases between .000 and .006 should work.
So I did a quick search and it looks like the Saami spec for a .223 chamber is between 1.4636" and 1.4736" at the datum line (using a 0.330" comparator to measure from this point) and for ammo it is 1.4666" -.0070" at the datum line. So I think it just comes down to manufacturing differences between manufacturers, not a major issue, just sounds like your dies are not yet bumping the shoulder any amount.
As others have already said, sort your brass and set your dies to bump the shoulder an appropriate amount and then get to loading up the ammo.
As others have already said, sort your brass and set your dies to bump the shoulder an appropriate amount and then get to loading up the ammo.
This!!!
The biggest thing I personally think you should do is pick out some of the smallest brass you can find out of the pack and work up a load using that. You want to stay really far away from the edges though. NOTHING near max pressures at all.
For blasting ammo it should be ok as long as you back way off the max charges.
That all said I am all for sorting first then loading.
For blasting ammo it should be ok as long as you back way off the max charges.
That all said I am all for sorting first then loading.
what do you mean by “smallest brass”?
Smallest volume. Case capacity. The only way to know is either through a lot of testing or by posting the exact brand/make of the various brass here and see if others have had experience loading it. The latter might give you a big head start but is still no substitute for careful load work up. Even more careful when using mixed brass.
One way you can proceed is to say get 5 cases of each head stamp and work up a load using the exact bullets/powder/primer and then work up until one of them starts to show pressure. The first one to demonstrate anything like that is generally going to be your baseline of 'not to be exceeded' charges.
That said all things considered taking the time to sort the brass into piles is worth it in my view. Then the next time you go brass shopping try to purchase stuff that is already pre-sorted.
The other stuff works but don't eff with safety.
It wasnt clear as to what you meant; op may also have misinterpreted that to mean smallest headspace or smallest casehead to shoulder datum or some other measure.
Also, i dont need an explanation on how to work up loads or sort brass. Nor do i agree with suggesting picking the head stamp with the case volume as there are no advantages whatsoever in doing that over picking any other headstamp with more capacity.
Ideally, you pick the head stamp in which you have the hightest number of servicable cases and work up a load for the rifle (as you mention), paying careful attention for overpressure signs.
Cases with low relative case capacity have you leaving performance on the table because you’re hitting pressure sooner and likely before you’re getting optimal velocity (ie velocity absent overpressure).
@Dot3 , here is a partial list of 5.56 case head stamps along with respective weight (in grains) so you have an idea as to which cases have what capacities (weight isnt a direct measure of case capacity but can be used to infer relative capacity if compared across multiple head stamps in context of different charge weights.
more weight = less capacity and less capcity = more pressure at a given charge weight relative to cases with more capacity. Focus on one headstamp at a time and work up carefully.
This is close to what I was going to say.
If you're sizing mixed brass I wouldn't worry about .006. Numbers are good but they will drive you crazy if you let them. Different brands may have a slight different alloy and/or hardness. The way you lube it and the amount of time you hold it in the die may make a difference too. I would just load and shoot it. Worry about the .006 if it happens to the same lot of brass fired the same number of times out of the same rifle.
No one offered that to you. Certainly not me.
Again no one asked you if you do or don't agree. If you don't agree that's fine. Not hurting my feelings at all. Post up your other solutions and move on with life. There are dozens of ways to approach this. None would be entirely right and none would be entirely wrong.
Lol. So you didn’t write all this shit in bold after answering my question? That was another alamo5000???
Looks like a fucking dissertation to me…
I don’t need anyone to ask me as to whether I agree or not to comment. Your solution, “pick the smallest brass” was poorly worded and asinine.
Again no one was speaking to you or posting to you until you decided to respond and try to pick a juvenile fight.
You injected yourself into someone else's conversation.
That's enough juvenile little boy.
Its an internet forum, not a private conversation you stupid fuck. If you don’t want anyone else responding to stupid shit you say, send it in a PM.
Beyond that, you have ZERO control over what others respond to or what they say.
Another dipshit for the ignore list…
It definitely can be done and done safely. It just depends on what kind of ammo one wants to produce. For general use range ammo, aka blaster ammo, it's fine provided safety precautions are followed. Trying to push every last case to the utter maximum might not be the best way in my opinion. But backing off on the charge will allow a lot of shooting while still observing safe reloading practices.
In short I have zero disagreements with what you said, merely adding in there a bit more information as I see it.
Again it depends on what the goal is. Sorting the brass (if it were me) would personally make me feel a lot better until I establish exactly what I am working with.
Of course its for "general use range ammo" if you have 20 different brands of cases are you going to sort and develop a load
for each one? And if you are just plain stupid and push loads to the limit you should not play this game and only use factory ammo.
Im not saying you personally "you" is everybody.
For my blasting ammo I load 24.8 H335 over a 55FMJ with a CCI450 or Win 41 primer in a 5.56 Nato chamber and touch steel plates out to
400 yards with a 1x4 optic. Fired over 2k of this load this summer without a single issue.
Oh believe me, I get exactly what you are saying. "You" should be taken personally by everyone. Because nobody wants to see "you" with a blown up rifle (or blown up face), missing fingers or worse.
As a general guideline mixed brass should be for range ammo only. It might be lower-ish power relative to some other ammo but it should function just fine in almost any AR15. If "you" want to do more than that and start pushing the envelope "you" need to wait and invest in some quality components.
That is not being a butthole and talking about 'poors' or whatever but rather a kick in the butt to keep it safe.
You and I are definitely on the same page. Not so much for some of the others on this thread.
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