I feel odd asking these questions since I've been handling an AR (M16 actually) for several years in the infantry.  Thing is, there was never a reason to know it intimately since there is no modifications needed or allowed.  Now that I am building one for use in a law enforcement capacity I have some questions:

What would be the proper twist on the barrel?

Why is one (1:7 or 1:9) better than the other?

Is there a big difference between forged and cast lowers?

Would an AR with minimal use really need one over the other (forged v. cast)?

Is there a specific type of parts I should buy (will parts labeled AR15 fit in parts labeled M16)?

Whats the difference between AR15 and M16 (besides full auto or burst)?

Is model 1 sales reputable? Is M&A parts?  (that's who I'm thinking about buying the rifle kit through)

Is there anything else you think I need to know or take into consideration?

Thank you very much for taking time to respond to this post.

Leo6223

Quoted: I feel odd asking these questions since I've been handling an AR (M16 actually) for several years in the infantry.  Thing is, there was never a reason to know it intimately since there is no modifications needed or allowed.  Now that I am building one for use in a law enforcement capacity I have some questions: What would be the proper twist on the barrel? 55-grain bullets:  1/12.  62-grain bullets:  1/9.  Very heavy bullets, like 80 grainers:  1/7. Why is one (1:7 or 1:9) better than the other? Only reason Uncle Sam uses 1/7 as far as I know is to stabilize the tracer round.  1/9 will give you slightly higher velocity with less wear, not that it is likely to matter in the real world.  But I would rather have 1.9, it is a good all-purpose twist. Is there a big difference between forged and cast lowers? Probably not, although forged is theoretically stronger the AR receiver is not highly stressed because the bolt locks directly into the barrel.  Forged looks nicer and commands easier and higher resale. Would an AR with minimal use really need one over the other (forged v. cast)? Nope.  I'd still pay the small amount extra and get forged. Is there a specific type of parts I should buy (will parts labeled AR15 fit in parts labeled M16)? Don't put anything M16 in your semi AR or The Powers That Be will be upset.  Parts that are not common to both are the bolt carrier and the entire trigger group.  Also beware that our politically correct friends at Colt use different sized hammer and trigger pins in their later model ARs than anyone else. Whats the difference between AR15 and M16 (besides full auto or burst)? See above. Is model 1 sales reputable? Is M&A parts?  (that's who I'm thinking about buying the rifle kit through) So I hear.  I used J & T and was happy. Is there anything else you think I need to know or take into consideration? Get a chrome lined bore.  Less wear, more durability, at least in theory more reliability. Thank you very much for taking time to respond to this post. You're welcome.  Good luck.  As always, YMMV.

What would be the proper twist on the barrel? Why is one (1:7 or 1:9) better than the other?

Unless you plan to shoot at extended ranges (over 200 yards) or with extra light (under 50 grains) or extra heavy (over 65 grains) bullets, barrel twist isn't a big issue.  The 1:9 twist should work fine.

Is there a big difference between forged and cast lowers?

No.  Just buy a Rock River Arms lower and be happy.

Is there a specific type of parts I should buy (will parts labeled AR15 fit in parts labeled M16)? Whats the difference between AR15 and M16 (besides full auto or burst)?

For the most part, AR15 and M16 parts can be mixed and matched.  It would be prudent, however, to keep any M16 parts that the BATF might have a problem with (especially the bolt carrier, hammer and sear) out of your AR15.

Is there anything else you think I need to know or take into consideration?

I suppose you should be aware of the legalities of "pre ban" and "post ban" configurations.  Even if you're a police officer, your personal rifle might not be exempt from the 94 ban.

I went the model1, M&A parts route with my first AR. I actually can't remember which one I bought it from. They are from the same area of the country and I'm not sure they aren't the same company. From what i've seen from others the J&T distributing sets are good. I am meticulous with my guns and clean them with 24 hours of every use even if it is just a few shots. After a day of shooting my gun from M&A, model1 I cleaned it and put it in the safe. I got a new AR soon after that so that one didn't come out of the safe for a while. When I pulled it out about a month later there was rust in the barrel and I had run a patch with hoppes on it through before putting it in the safe. Not real bad, some scrubbing and shooting and it's almost not noticable, but I don't think I'll ever buy another one that isn't chrome lined or SS.

My first AR functions great with no problems, even running thousands of rounds of wolf through it.

I would also buy a forged lower just because you only save like twenty bucks with the cast lower and $20 isn't very much on a gun your going to spend $600 on in total and you might be betting your life on.

BTW welcome to the board

Thank you very much for the responses (very fast at that).  As far as being exempt from the ban, I checked with ATF and LEO's are exempt from the ban.  They can put pre and post ban parts together to "manufacture" (their words) a rifle.  Only catch is once you leave law enforcement you have to either sell the weapon or break down the parts.  I think I will keep mine all post ban just to avoid that issue.  Thank you again for the information. It is greatly appreciated.




Leo6223

Quoted: Thank you very much for the responses (very fast at that).  As far as being exempt from the ban, I checked with ATF and LEO's are exempt from the ban.  They can put pre and post ban parts together to "manufacture" (their words) a rifle.  Only catch is once you leave law enforcement you have to either sell the weapon or break down the parts.  I think I will keep mine all post ban just to avoid that issue.  Thank you again for the information. It is greatly appreciated. Leo6223

I think this is very interesting since it does not seem to require that the rifle be used solely (or at all) for duty purposes, only that an LEO own it.  

So LEO's regardless of the duty status of the firearm, are excempt from the 94 ban.  WTF?

I can understand the pseudo thinking in regards to a duty firearm, but for a personal firearm? Again I ask WTF?  Why should an LEO's privately purchased and owned firearms be exempt from the rules the rest of us live by?

No flame on the original poster who is just taking advantage of a loophole in the law, but what's good for the goose is good for the gander so to speak. LEO personal weapons should also be subject to the AW ban rules OR NO firearm should be (preferably the latter.)

I guess some folks are just more equal.

Regarding LEO exemption from 1994 ban, unless you are putting together an NFA-registered machinegun I think you still want to stay away from M16

-- sear
-- trigger
-- hammer
-- disconnector
-- bolt-carrier, and
-- selector

Even if your gun doesn't act like a machinegun, if it has ANY of these parts, the ATF considers it a machinegun. Unless you're acting on behalf of a government agency, you're not supposed to put together a machinegun.

"ANY operational part of an M-16, not limited to, but including, trigger, sear, hammer, selector, or barrel under 16 inches in overall length(unless registered as a short barreled rifle), inserted into ANY civilian model AR-15, or copy, not registered as a 'Machine-Gun' will be looked upon as a felonious un-registered machine-gun "
      B.A.T.F.


___________________________________

Signpost Ahead

Light at the end of tunnel is the headlamp of oncoming train

Quoted: Regarding LEO exemption from 1994 ban, unless you are putting together an NFA-registered machinegun I think you still want to stay away from M16 -- sear -- trigger -- hammer -- disconnector -- bolt-carrier, and -- selector Even if your gun doesn't act like a machinegun, if it has ANY of these parts, the ATF considers it a machinegun. Unless you're acting on behalf of a government agency, you're not supposed to put together a machinegun.

there's some meshing of the '94 "assault weapons ban and the '34 (i think) machine gun legislation, i think.

per-ban vs. post-ban is the '94 legislation dealing with evil features such as flash suppressors, bayo lugs, collaspable stocks, etc.  oh, yeah, and special treatment for LEOs and such (no slam on LEOs, just pissed at the double standard.)

the M16/AR15 parts mixing issue deals with the '34 (again, i think) machine gun legislation, specifically, owning and "manufacturing" machine guns.  for this particular issue, i think it's safe to say i'd avoid mixing M16 parts with AR15 parts period.  put AR parts in the AR and leave the M16 parts to the M16 if you're lucky enough to get one.

as i understand it, LEOs are allowed to have the pre-bans for duty purposes with certain limitations (see Troy's post), but i didn't think they were allowed any special privileges under the machine gun legislation.  Troy?  how about some answers.  

Q: What would be the proper twist on the barrel?
A: 1:9

Q: Why is one (1:7 or 1:9) better than the other?
A: The 1:7 is better at stablizing smaller (shorter) bullets (smaller isn't better). The 1:9 is fine for 55 grain and perfect for 62 grain NATO rounds.

Q: Is there a big difference between forged and cast lowers?
A: Yes HUGE. The rifle as designed for a forged machine not cast.

Q: Would an AR with minimal use really need one over the other (forged v. cast)?
A: Yes. Why not spend an extra $10 on your $700 rifle and get one made as it was designed (forged)?

Q: Is there a specific type of parts I should buy (will parts labeled AR15 fit in parts labeled M16)?
A: Good ones.

Q: Whats the difference between AR15 and M16 (besides full auto or burst)?
A: by others...

Q: Is model 1 sales reputable? Is M&A parts? (that's who I'm thinking about buying the rifle kit through)
A: I bought a cheap kit from M&A some years back and it was alright. I'd rather see you go with Armalite or Bushmaster kits.

Q: Is there anything else you think I need to know or take into consideration
A: About a hundred things ... Get a chrome lined barrel and mil-spec parts and you'll do fine (Bushmaster!).

I own half a dozen AR's and built five of those.

Wow, at first I thought this was a pretty friendly site, then flames from out of nowhere.  As far as the information I got it came from the Firearms Technology Branch (FTB) of the BATF in written communication.  It states that the same rules apply to other post-ban assault weapons and hi-cap mags.  They must be purchased/used by an active LEO and must be sold upon leaving Law enforcement.  As far as being more equal or less equal or whatever you want to call it really is not pertinant.  I didn't create the law.  I am pretty surprised to see a little bit of anti-law enforcement attitude on the board.  Figured this for a LEO friendly site.  Regardless, if someone is interested I'll post the correspondence on the board from the BATF.  Oh yeah, as far as joe citizen- when I'm in my house sleeping, you bet your ass I want the coppers protecting my block to have all the firepower and goodies they can get their little hands on.  

I re-read the letter I got from ATF.  I think what it was saying (it was very wordy) is that if the Dept. Armor puts together the weapon than it is legal for me to use.  I'm not sure who would be responsible for selling if I leave Law enforcement.  I am making a call to the FTB of the ATF on monday to clear this up.  Believe me, I am the last one who wants to break the law, and no, I'm not one of those cops who believe they are above the law.  Troy, since it seems by general concensus that you are the resident expert on these matters, do you have a point of contact there at the ATF or know of someone or specific dept I should talk to?  Thank you again.  

Quoted: Q: Why is one (1:7 or 1:9) better than the other? A: The 1:7 is better at stablizing smaller (shorter) bullets (smaller isn't better). The 1:9 is fine for 55 grain and perfect for 62 grain NATO rounds.

Actually the 1:7 is for very heavy, long bullets. The 1:12 is for 55grn and smaller bullets.

This makes sense because the smaller the bullet the faster it is and a 1:7 would spin a 55 grn bullet very fast and could actually cause the bullet to rip apart due to centerfugal force.

Quoted: As far as being more equal or less equal or whatever you want to call it really is not pertinant.  I didn't create the law.  I am pretty surprised to see a little bit of anti-law enforcement attitude on the board.  Figured this for a LEO friendly site.  Regardless, if someone is interested I'll post the correspondence on the board from the BATF.  Oh yeah, as far as joe citizen- when I'm in my house sleeping, you bet your ass I want the coppers protecting my block to have all the firepower and goodies they can get their little hands on.

I know how you feel, I want as much firepower as possible for self-defense.

Spoke with the FTB this morning by phone.  They confirmed what they had written earlier.  If the dept amorer (yes most large agencies have an armorer who is licensed to do these things...mine is close to 4000 sworn) puts together the rifle kit, then it is treated the same as a LE stamped rifle.  I can use it for duty use but it must be sold to another LEO upon leaving the Dept.  Don't know what else to say.  THey may be wrong but this is the info they gave me.

Read through alot of the FAQ you gave a link to.  I can't argue that the info they gave me definately contradicts alot of what is on the board.  THe one thing the FTB never mentioned that seems to be an issue is paying the $200 tax to make the weapon.  I think I might just try to get my hands on an LE lower or just go with post ban parts to avoid the whole issue.

The site is leo friendly.......

Called ATF again to see if I could get them to put what they told me in writing and they kinda hem hawed around.  Basically they said "we don't see any issues with what you want to do but we don't want to put that in writing."  Well, I went with the post ban parts to put the whole issue to bed.  Got a bushy lower and a J&T M4 kit.  Thanks to who ever suggested J&T distributing.  THey have quality parts in their kits and the people are super friendly.  Great prices too.  I look forward to plinking at the range.  Oh yeah, I also ordered the shorty A2 stock which alleviates the whole issue with needing a collaspable CAR stock for body armor purposes.

Finally I want to thank all of you that took the time to answer my intial questions.  It was informative.