Chamber length guage

[Dildobaggins]

Trying to find a chamber length guage for a 6br. Is Sinclair the only company that makes them? Can't find anything else. I'd be happy to get one from Sinclair, but they are all out of stock. Or perhaps any ideas on how to make one?


Thanks fellas

 

[eschafer]

my earlier posted procedure won't work.. disregard... brain fart...

 

[nn8734]

Trying to find a chamber length guage for a 6br. Is Sinclair the only company that makes them? Can't find anything else. I'd be happy to get one from Sinclair, but they are all out of stock. Or perhaps any ideas on how to make one?


Thanks fellas

Are you referring to one of those cylinders that you insert the empty case into and see where it’s case head (or neck) is relative to the two different stepped surfaces and that presumably lets you know your “headspace” or oal is within “spec”?

 

[CK1.0]

You can make a dummy round and find exactly where the lands are by doing this:

 

[Schütze]

my earlier posted procedure won't work.. disregard... brain fart...

I think you got it correct if the op means to find max case length. I assume this was what he meant because he mentioned the Sinclair gauge.

 

[Dildobaggins]

Are you referring to one of those cylinders that you insert the empty case into and see where it’s case head (or neck) is relative to the two different stepped surfaces and that presumably lets you know your “headspace” or oal is within “spec”?

Yep, one of the cylinders that you insert. I just want to know my trim length. I found the reamer print for my NSS prefit, but I figured since I set the headspace, that number on the print would be invalid.

 

[Dildobaggins]

My apologies everyone, I should have been more clear on what I was trying to describe.

 

[Dildobaggins]

Couldn’t you use a set of dial calipers to measure oal / trim length against the reamer print figure?

I have a few of those and never use them (I did early on when i first started to reload but stopped once I realized they weren’t necessary once other measurements were taken).

That's what I was going to do, but the barrel is a variable shoulder, so I figured it wouldn't be accurate. I may be over thinking this. Haha

 

[spife7980]

The chamber length gauge is not the same thing as a go nogo. One is for case over all length, the other is headspace. Neither of those are where the bullet contacts the lands.


That said, just trim your cases to book spec and youll be fine. You wont gain anything by letting it grow another maybe 2 or 3 hundredths but you could make it pinch a bullet and fuck shit up.

 

[Molon]

Are you referring to one of those cylinders that you insert the empty case into and see where it’s case head (or neck) is relative to the two different stepped surfaces and that presumably lets you know your “headspace” or oal is within “spec”?

Yep, one of the cylinders that you insert. I just want to know my trim length. I found the reamer print for my NSS prefit, but I figured since I set the headspace, that number on the print would be invalid.

Are you two talking about the same thing? This is a Sinclair chamber length gauge . . .

....

 

[Dildobaggins]

Are you two talking about the same thing? This is a Sinclair chamber length gauge . . .

....

Yes I'm referring to what you have in the picture.

 

[Molon]

Yes I'm referring to what you have in the picture.

That's what I thought. People talking about chamber gauges and checking the distance to the lands are making this thread awfully confusing.

 

[Malum Prohibitum]

Are you two talking about the same thing? This is a Sinclair chamber length gauge . . .

....

I have never seen this tool before. Would you please explain to me what it is used for? Don't be afraid to dumb down your explanation for me.

 

[Molon]

I have never seen this tool before. Would you please explain to me what it is used for? Don't be afraid to dumb down your explanation for me.

The OP want's to know what the actual length of the chamber of his barrel is (the sections of the chamber made up of the case-head, body, shoulder and neck) not just what the drawing says that it should be. It's not uncommon for mass produced barrels to have a longer neck section than what the drawing might indicate, which contributes to a longer allowable trim length.

...

 

[Baron23]

I have never seen this tool before. Would you please explain to me what it is used for? Don't be afraid to dumb down your explanation for me.

Its for finding the maximum case length for your chamber with which to determine trimming set up. Idea is that you don't want to be much shorter than max as that will support the development of a carbon ring between the end of the case neck and that little lip where the free bore starts. I've seen a diagram that called that the 2nd shoulder

 

[Slobhunter2]

Pm me your number and a good time to call, I can explain how to make one, too much to type.

 

[Dildobaggins]

That's what I thought. People talking about chamber gauges and checking the distance to the lands are making this thread awfully confusing.

My bad. I thought when I mentioned "Sinclair" and "chamber length guage", it was clear.

 

[Dildobaggins]

Pm me your number and a good time to call, I can explain how to make one, too much to type.

Will do brother. Thank you

 

[RTH1800]

I have one of these if I can find it. PM if interested.

 

[Malum Prohibitum]

The OP want's to know what the actual length of the chamber of his barrel is (the sections of the chamber made up of the case-head, body, shoulder and neck) not just what the drawing says that it should be. It's not uncommon for mass produced barrels to have a longer neck section than what the drawing might indicate, which contributes to a longer chamber length and a longer allowable trim length.

...

Its for finding the maximum case length for your chamber with which to determine trimming set up. Idea is that you don't want to be much shorter than max as that will support the development of a carbon ring between the end of the case neck and that little lip where the free bore starts. I've seen a diagram that called that the 2nd shoulder

Thank you, both of you.

I am trying to learn a little more each day.

 

[Molon]

My bad. I thought when I mentioned "Sinclair" and "chamber length guage", it was clear.

It was clear to me.

...

 

[Slobhunter2]

Had a few minutes so I whipped one up, cut neck with Dremel, I trimmed the case just to clean it up and make sure it was square before I started.

 

[Slobhunter2]

Debur everything good, insert base of the bullet into the cut end of Short neck first and seat until it's flush with what used to be the case mouth, may want to use one drop of super glue here.

 

[Slobhunter2]

Insert into case, you may have to do some light sanding to get the neck tension you want.

 

[Slobhunter2]

Pull bolt and slip case rim under the extractor and reinstall, once you close the bolt it will set the max case length, remove case and measure.
I also drilled the primer out to 3/16 so I could slip a punch in there to tap the bullet back out a little for reuse.

 

[Dildobaggins]

Pull bolt and slip case rim under the extractor and reinstall, once you close the bolt it will set the max case length, remove case and measure.
I also drilled the primer out to 3/16 so I could slip a punch in there to tap the bullet back out a little for reuse.

Holy shit, that's genius. Thank you so much!

 

[Dildobaggins]

So I performed the method @Slobhunter2 shows here. Did it 5 times. I honestly didn't think it was going to work because My case looked like My 4 year old cut and polished it. My measurements were surprisingly very accurate. 1.5840-1.5830.

So final question. What should I trim my brass to? I was fireforming today and my Lapua brass started out at 1.5525-1.5565. After one firing they grew about. 005. After I FL size them I'm sure they'll grow a little more. At this rate, it'll never need to be trim, but I'd like them all trimmed to the same length. So what would y'all suggest?

 

[Dildobaggins]

Side note. That seems quite long for a 6br from what I'm reading, but I could be wrong, as I usually am.

 

[Haney]

So I performed the method @Slobhunter2 shows here. Did it 5 times. I honestly didn't think it was going to work because My case looked like My 4 year old cut and polished it. My measurements were surprisingly very accurate. 1.5840-1.5830.

So final question. What should I trim my brass to? I was fireforming today and my Lapua brass started out at 1.5525-1.5565. After one firing they grew about. 005. After I FL size them I'm sure they'll grow a little more. At this rate, it'll never need to be trim, but I'd like them all trimmed to the same length. So what would y'all suggest?

I would let it grow for at least a few firings . If you see a difference in length that you don't like you can trim them then . You are making a smart move by knowing your actual chamber measurements . As you have proven , no need to trim and give carbon a chance to gather .

 

[Haney]

Side note. That seems quite long for a 6br from what I'm reading, but I could be wrong, as I usually am.

Don't worry about it if you got repeatable results . Just more proof people trim brass blindly .

 

[Supersubes]

Its way easier to chamber a case and sticks your teslong borescope down the muzzle and took at the clearance directly. I have all those sinclair gauges but haven't used them for years.

 

[CK1.0]

I wouldn't bother trimming them until they get on the long side or if the lengths are wildly inconsistent and all over the place.

FWIW, I just got done running some Lapua 22-250Rem brass that I necked up to 6CM. I used it over 2 barrels, 14-15 firings, and I never trimmed it. Not even once. It started a little short (1.89" IIRC) and didn't grow nearly as fast as I thought it might. After 14 firings it was still only just slightly above SAAMI minimum (a little over 1.9").

The short-necked brass didn't affect things one bit. Great SD/ES numbers and small groups the whole time, the ammo shot great. No carbon ring or any of the issues people freak out about showed up.

That said, I used a 10" chamber rod and an AR chamber brush with a big cotton patch wrapped around it to really hit the chamber every time I'd clean the rifle (just a good thing to do every time anyway, but also to avoid any issues).

 

[Malum Prohibitum]

No carbon ring or any of the issues people freak out about showed up.

That said, I used a 10" chamber rod and an AR chamber brush with a big cotton patch wrapped around it to really hit the chamber every time I'd clean the rifle (just a good thing to do every time anyway, but also to avoid any issues).

Any kind of solvent?

 

[CK1.0]

Any kind of solvent?

Duh, sorry: Bore Tech Eliminator, their nylon brushes, cotton patches, that's it., for the life of the barrel, nothing else.

 

[Haney]

Its way easier to chamber a case and sticks your teslong borescope down the muzzle and took at the clearance directly. I have all those sinclair gauges but haven't used them for years.

How do you get a precise measurement ? I can understand seeing the gap, but how do you determine just what that gap length is ?

 

[Supersubes]

How do you get a precise measurement ? I can understand seeing the gap, but how do you determine just what that gap length is ?

You dont. You can see if the case mouth is butting up against the end of the chamber, or perhaps your max trim length actually has a bunch of clearance.

 

[Malum Prohibitum]

You dont. You can see if the case mouth is butting up against the end of the chamber, or perhaps your max trim length actually has a bunch of clearance.

If there is clearance, what do you do? Hope future shooting and reloading without trimming will finally stretch the neck enough to fill in the gap?

 

[spife7980]

If there is clearance, what do you do? Hope future shooting and reloading without trimming will finally stretch the neck enough to fill in the gap?

Yeah, and all for zero tangible gain.

 

[Supersubes]

If there is clearance, what do you do? Hope future shooting and reloading without trimming will finally stretch the neck enough to fill in the gap?

There’s no need to fill the gap, so no.

 

[Haney]

There’s no need to fill the gap, so no.

Just let it fill with carbon , no gap will remain .