I used a sinclair chamber length gauge and measured my chamber of my GAP 308 to be 2.040 +/- .002, now is that normal for it to be of that length? Should I only trim my brass when it gets to that length?
chamber length gauge ?
- Thread starter jerseymike
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Re: chamber length gauge ?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jerseymike</div><div class="ubbcode-body">I used a sinclair chamber length gauge and measured my chamber of my GAP 308 to be 2.040 +/- .002, now is that normal for it to be of that length? Should I only trim my brass when it gets to that length? </div></div>
That's pretty long. I can let my necks grow to 2.020" and I think that's a bit long.
People like Victor here, will subract .005" from their measurement, so your 2.040" might be 2.033" when taking into account that +/- .002" variance.
This being said, I'd try and find the longest 308 case I could, size it, measure carefully the edge of the case mouth, in a few places and then chamber the round. Extract and remeasure. If you find any pinching, at X length, you know you've gone too far.
On a custom barrel, I'd think that 2.040" would be a bit long.
Chris
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jerseymike</div><div class="ubbcode-body">I used a sinclair chamber length gauge and measured my chamber of my GAP 308 to be 2.040 +/- .002, now is that normal for it to be of that length? Should I only trim my brass when it gets to that length? </div></div>
That's pretty long. I can let my necks grow to 2.020" and I think that's a bit long.
People like Victor here, will subract .005" from their measurement, so your 2.040" might be 2.033" when taking into account that +/- .002" variance.
This being said, I'd try and find the longest 308 case I could, size it, measure carefully the edge of the case mouth, in a few places and then chamber the round. Extract and remeasure. If you find any pinching, at X length, you know you've gone too far.
On a custom barrel, I'd think that 2.040" would be a bit long.
Chris
Re: chamber length gauge ?
The whole point of measuring the chamber length is when you are trying to make the brass as long as the chamber will handle. This way the powder ignition doesn't erode the throat of the chamber as much as if the cases are trimmed to the SAAMI specs. I only do this in bolt action match chambers. Semi auto rifles get trimmed to regular length.
The whole point of measuring the chamber length is when you are trying to make the brass as long as the chamber will handle. This way the powder ignition doesn't erode the throat of the chamber as much as if the cases are trimmed to the SAAMI specs. I only do this in bolt action match chambers. Semi auto rifles get trimmed to regular length.
Re: chamber length gauge ?
Well i have measured it several times, and i keep coming up with 2.040, which i feel is a bit long. Should i wait for my brass to get to this length or should I forget about it and cut them to saami spec. Will having a chamber that long have any negative effects on accuracy or chamber pressure?
Well i have measured it several times, and i keep coming up with 2.040, which i feel is a bit long. Should i wait for my brass to get to this length or should I forget about it and cut them to saami spec. Will having a chamber that long have any negative effects on accuracy or chamber pressure?
Re: chamber length gauge ?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jerseymike</div><div class="ubbcode-body">Well i have measured it several times, and i keep coming up with 2.040, which i feel is a bit long. Should i wait for my brass to get to this length or should I forget about it and cut them to saami spec. Will having a chamber that long have any negative effects on accuracy or chamber pressure? </div></div>
I guess it is what it is?
Personally, in your situation, I'd first trim to 2.015 and see how things work. If you don't get soot around your necks, you're getting a good seal and you're still officially 'safe'. I'd then let them grow to maybe 2.820" and see. This is where I can go to, so I keep it a few thous below this and see no issues. I have a big batch to trim and I'm probably going to go to 2.812", to allow some room to stretch.
I'm not one of these guys where all my cases have to be exactly at X, Y or Z.
Chris
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jerseymike</div><div class="ubbcode-body">Well i have measured it several times, and i keep coming up with 2.040, which i feel is a bit long. Should i wait for my brass to get to this length or should I forget about it and cut them to saami spec. Will having a chamber that long have any negative effects on accuracy or chamber pressure? </div></div>
I guess it is what it is?
Personally, in your situation, I'd first trim to 2.015 and see how things work. If you don't get soot around your necks, you're getting a good seal and you're still officially 'safe'. I'd then let them grow to maybe 2.820" and see. This is where I can go to, so I keep it a few thous below this and see no issues. I have a big batch to trim and I'm probably going to go to 2.812", to allow some room to stretch.
I'm not one of these guys where all my cases have to be exactly at X, Y or Z.
Chris
