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Posted: 1/13/2004 6:50:17 AM EDT
| What's the best thread to attach a better variety of barrel accessories: 1/2x28 or 1/2x32? |
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As for 1/2" threads both Colt and my former employer don't use them for exactly the reason stated and to prevent the accidental use of .223 muzzle devices. Some companies use the size bc the taps and dies are a common (cheap/available) one. Others use them due to the number of accessories available. Given a bullet/bore diameter of .355" and a minor diameter on the 1/2-28 threads of .4551" max you're left with .1". Divided by 2 you have a wall thickness of .05". Recommended minimum wall thickness for CF rifles is .1". Luckily, the 9mm is a lower pressure load but problems could develop with the combination of heavy (full auto) use or large (heavy/long) muzzle cans. 5/8" threads are a better choice but 1/2" threads do work. GemTech offers them as an option with some of their cans IIRC. If I had to make the choice I'd go for the 28TPI. |
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Quoted: I think the euro makers use reverse thread? Europeans use metric, like 16X1mm, either RH or LH. Some guns intended for sale in this country may use Unified threads for use with domestic accessories. ETA, you'll often find 32TPI on handgun barrels due to the shorter shanks available on those barrels. |
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Quoted: Quoted: Colt 9mm SMG threads are 1/2x36. Why not use those? The "36" is a rather fine thread, that much easier to cross thread in a hurry. 5/8-24 be a better choice for 9mm. |
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He has ordered a M4 DOE upper, they come with a threaded 3 lug. As far as accessories go suppressors, flash hiders, blank firing adapters, and grenade launchers for the MP5 will fit the 3 lug. The threads at the tip of the 3 lug will take the same accessories but must be screwed on to the barrel instead of just snap on like with the 3 lug. When I first started making these I thought the 1/2X28 was going to be ordered far more than the 1/2X32 but I was wrong, the 1/2X32 is far more popular. As far as 1/2 inch thread on a 9mm barrel goes, I have never seen a failure or split barrel. If the 1/2 inch threads were a problem I don't think HK would have used them on the MP5 or Colt would have used it on there 9mm guns. I have been involved with both theses guns for over 10 years and have never seen a failure or split barrel because of 1/2 inch threads. Mike @ TSC CO. [img]http://img.villagephotos.com/p/2003-3/64578/PGNKHUZWJMPDODBUQYUM-DSC00077.JPG[/img] |
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