ADA: Ask Doc Anything!

[DocsMachine]

I think its CMI

-That rings a bell. That does kind of strike me as the brake end that was on the ThunderPig (I think it was...) that I had briefly.

I hd no idea they had a "straight rifled" barrel, and I know mine sure wasn't.

Doc.

[Magmoormaster]

I'm fairly certain it is indeed a Tru-Flight.

[flyweightnate]

You just answered so many questions with that answer! Now I just need a mnemonic to remember which is which.

[Cunha]

Doc,

Any idea, Who was the manufacturer of this 14" AC threaded barrel?

I think its CMI

[Carp]

Thanks for the effort Doc, I want to say it resembled a Thunder Pig Tru-flight( or whatever it was called).

[DocsMachine]

Is Doc going to fix the time line or otherwise get back with Cara? We have had enough bad things happen in 2020 already.

-Well, the popular theories so far is that's not Cara, it's her sister, or that it's Cara, but she's married to the snow leopard, or that's Cara, and Miki is now a snow leopard, or- and this is my favorite one- that in this timeline, Morty and Cara met last weekend, and it didn't go well. In this timeline he's spent much of the last week trying ever-more-absurd rom-com nonsense to try and win her over, which just annoys her more and more.

And if A, I was a better writer, and B, I really wanted to yank readers' chains, that would have been a great storyline.

'Course, if I wanted to yank your chains, I'd also cut away back to the tourney, tomorrow.

Except I think I'd be lynched.

Doc.

[DocsMachine]

Any idea, Who was the manufacturer of this 14" AC threaded barrel?

-Boy, that muzzle brake design seems familiar, but the only barrel I can recall with a sort of "straight rifling" was the old J&J stuff. Sorry I can't help.

Doc.

[Carp]

Doc,

Any idea, Who was the manufacturer of this 14" AC threaded barrel?

[delta5]

-Certainly. I have a small handful of unthreaded adapter blanks specifically for that kind of thing- though actual requests are few and far between.

There is an additional surcharge, since they're custom-machined, of course, but if that works for you, drop me an email and we can go from there.

Doc.

Email sent!

[Big Phil]

Is Doc going to fix the time line or otherwise get back with Cara? We have had enough bad things happen in 2020 already.

[DocsMachine]

There are two basic classes of polyurethane, ester and ether base. Ester base polyurethane is cheaper, but undergoes hydrolysis much more readily than ether base. It reacts with moisture in the air over time and disintegrates.

-Excellent data. I had suspected it had to do with quality, but didn't know the actual mechanism.

Doc.

[DocsMachine]

Would you be willing to make a twist lock adapter in a different thread? Like say, Spyder?

-Certainly. I have a small handful of unthreaded adapter blanks specifically for that kind of thing- though actual requests are few and far between.

There is an additional surcharge, since they're custom-machined, of course, but if that works for you, drop me an email and we can go from there.

Doc.

[delta5]

Would you be willing to make a twist lock adapter in a different thread? Like say, Spyder?

[Araphel]

There are two basic classes of urethane, ester and ether base. Ester base urethane is cheaper, but undergoes hydrolysis much more readily than ether base. It reacts with moisture in the air over time and disintegrates.

[DocsMachine]

Is this a crazy idea or have I just been unlucky so far?

-Neither. What you're seeing is a common issue with older markers- the O-rings are made of one flavor or another of polyurethane, and at some point they start to depolymerize.

In other words, they break down and turn into a goo.

I have seen it countless times, both in my own and customers' guns, but near as I can tell, there's no rhyme or reason as to what causes it. For example, I have, in my shop, a baggie of tank O-rings, that I bought from a field that was closing down, back in 2001. Those tank O-rings, today, are still perfect, it's still my bag of go-to seals for tanks, regs and whatnot.

However, in that same room, stored in the exact same conditions, is my old Sheridan Equalizer, which I bought in 1995. When I went to try that thing out again a couple of years ago, I had to rebuild the entire regulator, as every seal in there had turned to goo.

And it's not the oil I use- that gun has never seen anything but KC Troublefree/Outlast, a full synthetic gun lube. And I used that same lube in my green Autococker the last time I fired it in anger (roughly 1998) and when I aired it up a few years ago, a few drops of KC was all it needed to work perfectly.

My best guess- subject to change and additional data- is it has to do with the quality of the O-rings. Good seals made by a name-brand company? They probably last nearly forever- the last time I was actually inside my 'Cocker was probably 1996 or 1997. Seals made by some cut-rate supplier, or some Chinese fast-buck shop? Probably made of inferior materials that work fine for however many years, and then start to degrade.

Yeah, it's a hassle to have to fully rebuild a marker, to say nothing of a small fleet of them. But assuming nothing got damaged by being overpressurized or something, on the plus side most markers use fairly common off-the-shelf O-rings. You can get O-ring kits for most common markers, and even obscure ones just take a bit more work to find.

The only sticky point in most cases is reg seals, which in a lot of cases are proprietary to that regulator. But even here, replacements can be made- I have a pile of sheet urethanes and punches on hand, and can make nearly any seal you might need. Even those oddball figure-eight seals for the Equalizer.

Doc.