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Posted: 7/3/2009 2:24:18 PM EDT
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I picked up a Model 1 Sales upper a few weeks ago on EE. A 20 Inch nonchromed HBAR M4 in 5.45x39. I can't decide whether I should leave it at 20 inches or cut it down to a Dissy length. Is there any advantage to the 3+ inches in front of the gas block / sight besides dwell time? I was thinking about cutting it to 16.5 inches, having it threaded and crowned, and then opening the gas port to 7/64". If that doesn't work out well I could always have a midlength gas system put on, but at that point I could have just bought a new upper for the cost expended by adapting, experimenting and paying FEDEX bills. The argument for accuracy seems to be that 16 inches is plenty for the .223/5.56 round in most cases, and I have a 24 inch Varmint upper for reaching out, but I don't know how barrel length affects the 5.45 round. Does anyone have any experiences, success/horror stories or advice? I used to swap big block Chevys into my 2nd generation Formula Firebirds to go racing with better odds, so it's not like maintaining purity and original spec's are important to me. This is never going to be a collector piece, unless the BATFE makes 2A null and void. I'd really like to get info from others who have been there instead of trying to write this book all over again for myself. Thanks for any help or advice you can give. |
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