Archive for June 30th, 2009
Different metrics
When you buy barrels for most guns, you care primarily about brand (as a proxy for quality), length, and twist. Perhaps some other features are important, like chamber tightness, metal, or finish. Quality of the threads is usually down the list, if on the list at all. Most muzzle breaks are designed to be open enough to not impede the development of sound (I’m only aware of two that aren’t); many precision rifles have no muzzle device at all.
Talk to people about barrels, and the same makers float to the top; however, among people that shoot suppressed rifles, different names populate the list.
LMT wasted some of my money with a fucked up barrel, so I’d trust ADCO too. I would have thought from reading all of Wes Grant’s posts that they were gold plated miracle sticks, but my barrel thread is so far out I’m afraid to shoot cans on it now. On a .275 bore it apears to lean far enough to nearly be parallel with one of the sides.
It comes down to how perfect your threads are, or how much meat you have left to re-thread. If you’re building an AR15 to suppress, the best bet is to buy a non-threaded barrel and have either a well-known company (ADCO) or your suppressor maker (Gem-Tech) thread it. They know how important it is that the threads are aligned with the bore, not the exterior of the barrel.
Another metric that is supremely important for suppressor owners is ammo quality in terms of run-out; you need to inspect each round you send down the pipe. Period. If you don’t, you could end up with an endcap strike on your brand new suppressor:
If you ignore the light strike, you might end up with this:
That’s a pile of $100 bills thrown on a fire; the ATFE no longer allows you to repair a suppressor tax-free if it involves modifications to the “can” portion.
In the old days, you built suppressors in certain ways (with wipes) because they worked and were cheap. Once the ATFE changed what a wipe was and what was allowed (wipes verboten), the market evolved from loose tolerances and wipes to modern wipeless cans with tight tolerances. If you had a strike, you re-serialized a new can and no additional tax was paid. The ATFE changed those rules; now the trend is toward cans that may be disassembled and repaired without welding. Furthermore, they’ve relaxed the rules on wipes a little. The market continues to react to what the ATFE says is legal today; you should pay attention to the type of can you buy and adjust your metrics for quality appropriately. Threads that work for a flash hider will destroy your suppressor, and ammo that’s fine for blasting (XM anything) will do the same.
