Smallest Bore Twistlock Mag Barrels?

[Meleager7]

Would you guys know which brands / models of mag twistlock barrels had the smallest bore sizes?

I know about the mag freak backs, and Doc's adapter, but I am looking for a more period correct twistlock, that might have a better time avoiding rollouts.

i have a 16" All American twist lock (black back) and it is roll out city, even with a brand new detent from AGD !

[Bulldogr6]

I've always wondered if there was someone out there who could freak bore one of the twist lock barrels.

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[Grendel]

IIRC my old Lapco SS Autospirit was 0.687 most likely the smallest twist lock barrels for Mags.

[Toestr]

Try putting a strip of tape tight over the raised bit on the back of the plastic detent. If not, try a wire detent.

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[NONOBLITUS]

I seem to have good luck with an old J&J

[Myrkul]

The only two options I found that prevented rollouts was a "smaller" ( 0.69 or less) bore barrel with a bent in wire detent or a factory dual detented barrel. A docs adapter or a single plastic detent was rollout city. I believe the R/Ts came stock with dual detents. Right now I'm just using a stock looking barrel that happens to be dual detented. It's probably massive at 0.691 and I still had to double up on the barrel "O" Rings, but it has not had a double feed or a rollout since I started using it.

[Brokeass_baller]

You have to be careful with small bore mag barrels. Poor tolerances can cause bolt stick. Best option is honestly an adapter, likes Doc's or that one Canadian company. That way you have a controlled bore size.

[DocsMachine]

-The smallest actual bore you'll likely find is .688", Much smaller than that, like .686", and you'll start getting bolt stick. I have to make my adapters .688-.689" because anything smaller and L10 bolts will stick in them.

If you're getting rollouts even with my adapters, I'd look hard into trying another brand of paint (if that's even an option, and I know it's not for some) or I can easily add a second detent to the adapters. I do that by request on occasion, though unless your paint is sub-.670", it's generally not necessary.

As for "Freaking" a 'Mag barrel, that's a lot tougher than doing a standard 'Cocker tube. On a 'Cocker you can just bore in from the breech- easy peasy. With a 'Mag, you have to leave the breech alone, which means boring in from the front. The basic process is the same, but now you have to machine the end for a tip or other 'cap' to retain the insert.

Not a huge issue, but not as many people can do it, at least do it well and for a reasonable cost. There's a couple 'Mag "Bull" barrels out there that I made into 'sleepers'- the breech end unscrews to replace the insert, and when assembled, the whole thing looks classic-stock.

It's a neat mod, but the problem is half the time you want to remove the barrel, the front starts to unscrew rather than unlocking from the twist-lock pin.

The 'right' way to do that kind of mod, therefore, is to bore and thread the end for a Freak tip, so you can just grab the body to unlock it. And at last in my shop, that's a $100 mod, and most people will instead just go with the 'Cocker adapter.

Doc.

[Brokeass_baller]

OP, for what it's worth, I've been using an adapter from Doc for 15ish years, and have never had issues. I run it single detent and a Freak kit. It's a worthwhile investment.

[Meleager7]

thanks guys, i'll keep an eye out for dual detent twistlock barrels.....failing that it'll be Docs adapter !

[Grendel]

I like Doc's adapter really no need for roll outs if detent is put in there correctly and now you just use AC threaded barrels. Definitely would not under bore with Doc's adapter but slightly overbore is what I do with my mag that way less chance of barrel breaks but still reasonable efficiency (not that I worry about that much).

[Dusty Bottoms]

I've run at least seven Doc's adapters on mags and never had a problem with roll outs or double feeds with any of them. To back up what others said, I had a stainless Lapco Autospirit barrel that was .686 my Level 10 bolt would get jammed in it. It was totally unusable.

[M98punk]

What’s the bore on the mag Infiniti barrels?

[Jordan]

I've run at least seven Doc's adapters on mags and never had a problem with roll outs or double feeds with any of them. To back up what others said, I had a stainless Lapco Autospirit barrel that was .686 my Level 10 bolt would get jammed in it. It was totally unusable.

That's common and fixable... the spot on the bolt tip where it's brazed together needs to be machined down a few thou.