0 Headspace Chamber?
- Thread starter Ronin22
- Start date
Load a dummy round with and existing bullet but no powder or primer. See if it will chamber and extract. If it extracts fine measure the overall length and compare it to the loaded measurements. If the dimensions are the same and the bolt closes, it is probably OK, but you will need to start loading a bit low just to see how the brass looks. If pressure signs look normal, enjoy.
If it's a bit small you will reach pressure a bit sooner (slightly less case volume), but other than that, you should be good to go. All virgin brass is sized pretty small to begin with, so should fit fine. And after you fire it once, it's formed to your chamber, so just size and go as you normally would.
I did precisely that. It’s not crushing the virgin brass at all.
What is "Benchrest specs"?
Is it a cartridge you ever would like to be able to shoot factory ammo in? Do you know your dies will size enough without grinding down on them or the shell holder? I dont think I'd be satisfied with such a headspace.. especially if those two items turned into headaches.
Is it a cartridge you ever would like to be able to shoot factory ammo in? Do you know your dies will size enough without grinding down on them or the shell holder? I dont think I'd be satisfied with such a headspace.. especially if those two items turned into headaches.
Benchrest chamber specifications prioritize extreme accuracy through minimal and precise dimensions, with exceptionally tight, custom-designed clearances for the neck, body, and throat compared to standard production rifles.
Took me 5 seconds to copy pasta that.
The more I think about it, I typically shoot virgin brass only .002 stretch. I have AI I shoot with resistance on the bolt. I just never had one come back so tight.
It’s a 26” 708 MTU on ARC Nucleus action. I would have thought dude would know nobody shooting that cartridge Benchrest!
It’s a 26” 708 MTU on ARC Nucleus action. I would have thought dude would know nobody shooting that cartridge Benchrest!
WHAT CARTRIDGE?????The more I think about it, I typically shoot virgin brass only .002 stretch. I have AI I shoot with resistance on the bolt. I just never had one come back so tight.
It’s a 26” 708 MTU on ARC Nucleus action. I would have thought dude would know nobody shooting that cartridge Benchrest!
If your die has enough room to adjust the required amount.
This is the problem I had, he head spaced off a piece of brass when the actual shoulder was supposed to move ahead in a wild cat, once the brass was fired in that chamber I wasn't able to size the body or move the shoulder and it was super tight.
Other problem I had once was he head spaced a new barrel off a piece of brass and I had ammo sitting from the last barrel, that ammo would barely go in the gun. Not a huge deal but still sucked.
I get that. After 3 barrels of .260 that shot lights out, I put on a barrel I bought on an impulse that I cannot shoot my loads through. I can shoot factory ammo through it and will now load to that headspace and throat, but… It’s a bit of a shock when you first realize the difference.
Not sure if I’ll buy another barrel to shoot my other regular loads from (and the 200 rounds I have loaded) or not. Probably.
In and of itself, it’s fine to have a tight chamber.
Some potential concerns:
Can your sizing die reproduce the required size case? If the chamber is cut to the minimum acceptable dimension and your sizer is cut a little fat, you could end up not being able to get back to the “small” size of factory new brass. This is unlikely, but guys who do run tight chambers often have sizers made or selected to be small enough.
I’d be more worried that your guy cut the neck smaller than you want. Figure out what the standard neck size is for WHATEVER CARTRIDGE WE ARE TALKING ABOUT and make sure yours isn’t smaller than that…or neck turn. For example, a 6mmBR will often use a “no turn” neck dimension of .272”. If your neck is .269”-.270”, which are pretty common dimensions for benchrest guys, you can expect to have to neck turn immediately or after a firing or two.
Some potential concerns:
Can your sizing die reproduce the required size case? If the chamber is cut to the minimum acceptable dimension and your sizer is cut a little fat, you could end up not being able to get back to the “small” size of factory new brass. This is unlikely, but guys who do run tight chambers often have sizers made or selected to be small enough.
I’d be more worried that your guy cut the neck smaller than you want. Figure out what the standard neck size is for WHATEVER CARTRIDGE WE ARE TALKING ABOUT and make sure yours isn’t smaller than that…or neck turn. For example, a 6mmBR will often use a “no turn” neck dimension of .272”. If your neck is .269”-.270”, which are pretty common dimensions for benchrest guys, you can expect to have to neck turn immediately or after a firing or two.
Good points made. I selected the 7mm-08 reamer for the job, and it has .318 neck. Alpha brass OD .314 for .004 clearance.
I got myself into neck turning in the past when I sized down Lapua 308 cases to 7mm and wound up with zero clearance. So neck clearance is always at the forefront of my mind. The smith had a match reamer with a .312 neck. I said no fucken way. Lol
My initial loads are pretty conservative already factoring in the reduced case capacity of Alpha brass. Though I might only get to the second powder weight charge. We shall see.
I got myself into neck turning in the past when I sized down Lapua 308 cases to 7mm and wound up with zero clearance. So neck clearance is always at the forefront of my mind. The smith had a match reamer with a .312 neck. I said no fucken way. Lol
My initial loads are pretty conservative already factoring in the reduced case capacity of Alpha brass. Though I might only get to the second powder weight charge. We shall see.
For the guy doing the barrel, too short is an easy fix, too long is a little more complex. My opinion, as someone who chambers barrels, it should always close on a go and should always not close on a no go. That’s .004 to work with and in this world, that’s a mile.
I’d want it fixed…but I’m anal like that. This is why some guys (myself included) wants the action to do a barrel. Prefits are great all the way up until they ain’t.
Good luck.
I’d want it fixed…but I’m anal like that. This is why some guys (myself included) wants the action to do a barrel. Prefits are great all the way up until they ain’t.
Good luck.
Let me sneak a head space question in here please OP . Warrantied AK was returned to me with a new gun [riley 7.62x39] and I checked it right out of the box and it passed the go no go gauges , 2 months and 150 rounds later the bolt will not close on the go gauge [about a quarter inch from battery ] . rifle was misfiring with what looked like good primer hits AND doubling . Its on its way back to riley for another new newer gun . sup with the head space ?
I think you should post this in the Semi-Auto section. Get more attention to it as it's own thread.
Initial 20rnds load development:
All new brass chambered just fine.
Shoulders didn’t grow even .0005
Case necks let a bullet slide in smooth with about .001 clearance
SRP didn’t ignite W760 good at all. Some delay ignition. N540 is doing it though.
Forgot to maintain my ears on that .030 DTL group…(Taylor’s Compromise)
All new brass chambered just fine.
Shoulders didn’t grow even .0005
Case necks let a bullet slide in smooth with about .001 clearance
SRP didn’t ignite W760 good at all. Some delay ignition. N540 is doing it though.
Forgot to maintain my ears on that .030 DTL group…(Taylor’s Compromise)
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Excellent, not surprised that you had minimal growth. I used to just neck size my BR brass.
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