why isnt the m4a1 available as a mid length set up yet?

[lysander]

Well, if it had a mid-length gas system it wouldn't be an M4A1, would it?

[tom12.7]

Disadvantage:

No more bayonet

As insanely stupid as this sounds, this is an actual push against it.

[Find ManBearPig!]

Disadvantage:

No more bayonet

As insanely stupid as this sounds, this is an actual push against it.

Uh, didn't you know, bayonets obviously turn perfectly good sporting rifles into dangerous assault weapons. That's why Bill Clinton had to ban them back in the 90's. Think of the children!

[readyfireaim]

Well, if it had a mid-length gas system it wouldn't be an M4A1, would it?

maybe they should have a carbine and mid length option, i mean after all we do like having choices dont we?

[WS6]

Tell me then. List the advantages of a mid-length gas system in a 14.5" barrel, with data to support each point. So far I'm just seeing a bunch of derp and "feels".

Lower port erosion rates
Lower chamber pressures at unlocking event
Longer rails for those who prefer pinned fsb.

All 3 of those are either easily observed, or a product of physics. No specific source should be necessary I wouldn't think, but consider also that colt Canada just went middy.

[WS6]

I think the reliability issue with middy 14 inch is mostly due to many of them having the same gas port size as 16 in middy.

If .076 is the optimum/ideal for 16 in mid then I think it'd be a good idea to increase the port size of 14 in mid to .079 or .080

Or how about just adopt the KAC SR16 and be done with it? Everything I read about it sounds like it is the best DI AR on the market right now.

0.080 is very gassy on a 14.5 middy. 0.074-0.076 is the sweet spot.

[Brahmzy]

0.080 is very gassy on a 14.5 middy. 0.074-0.076 is the sweet spot.

Not sure about that... I've had occasional reliability issues with .750, .081 14.5 middies before, with weak ammo.
I can't imagine .074 being a sweet spot for reliability. I guarantee it wouldn't be a sweet spot.

[readyfireaim]

Not sure about that... I've had occasional reliability issues with .750, .081 14.5 middies before, with weak ammo.
I can't imagine .074 being a sweet spot for reliability. I guarantee it wouldn't be a sweet spot.

would you be more specific about what types of problems youve encountered before,enquiring minds would like to know

[WS6]

Not sure about that... I've had occasional reliability issues with .750, .081 14.5 middies before, with weak ammo.
I can't imagine .074 being a sweet spot for reliability. I guarantee it wouldn't be a sweet spot.

DD uses 0.076 and works fine with anything you shove in the chamber.

[Fluffy Bunny]

Tell me then. List the advantages of a mid-length gas system in a 14.5" barrel, with data to support each point. So far I'm just seeing a bunch of derp and "feels".

That's a fair question. I like a pinned gas block & front sight; middy gas give me a longer handguard + sight radius. Carbine and middy uppers cost the same so this one advantage is all I need. As for dependability if I buy a upper from a reputable name I expect it to work carbine or middy, or it should not be sold.

If you want to talk technical data I'm not up the challenge, sorry.