Another Gun in a Box - AR15 Pistol Build

[Hawk]

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[AJRB]

In my 7.5 I use a spikes tactical T2 buffer which weighs out close to an H2. I also run a sprinco heavy (red) buffer spring. I have not had one malfunction yet with this combination, knock on wood.
I also saw all the various balistics advice on barrel lengths, but seemed irrelevant to me for what I'm using an AR pistol for. If I want to shoot long range and get max balistics out of any ammo, I'll put down the pistol for a standard length carbine.
How important are balistics on a cqb AR? For example if SBR's and pistols purpose of use is clearing rooms or in an urban environment, engaging targets between 5-15 yards how much do balistics come into play?

[spacemanvic]

If you haven't already done so, I looked through my bookmarked sites and found it for $104.27 + $8.99 flat rate shipping.


They sell for $145 most everywhere else.
I got mine from Tombstone Tactical for $108, but that sale price is no longer in effect.

Not yet, looking to see if my distributors can get it, that way it's close to cost for me. Yeah I saw the YT SBR video, then showed it to some of the guys at the shop. You picked a winner device!

[arjohnson]

In my 7.5 I use a spikes tactical T2 buffer which weighs out close to an H2. I also run a sprinco heavy (red) buffer spring. I have not had one malfunction yet with this combination, knock on wood.
I also saw all the various balistics advice on barrel lengths, but seemed irrelevant to me for what I'm using an AR pistol for. If I want to shoot long range and get max balistics out of any ammo, I'll put down the pistol for a standard length carbine.
How important are balistics on a cqb AR? For example if SBR's and pistols purpose of use is clearing rooms or in an urban environment, engaging targets between 5-15 yards how much do balistics come into play?

If the barrel becomes to short for a 5.56 it loses terminal ballistics, means the round isn't as effective as it should be. It seems that anything bellow 10" it starts losing velocity and energy pretty fast, which means the round won't due what's it's designed to due.

The 5.56 was originally designed for a 20" barrel, anything less it starts losing both velocity and energy. A 55 grn FMJ will have about 1300 ft lbs of energy at the muzzle, a 7.5" barrel will have about 550 ft lbs, that's a big drop.

What I would do is use ammo that will work better from a shorter barrel to help make up for the loss of energy. Maybe something like Black Hills 50 grn Barnes TSX, seems to be a good choice for short barrels.

[Emptymag]

KNS Anti-walk Pins...

Holy freakin' pain in the ASS to install, Batman!
It must have taken me 45 minutes to figure out a way to get the pins in.

"Apply pressure on the top of the hammer until the hammer/trigger holes line up."

Yeah, OK.

I applied pressure alright. I took some pics that I'll post when it's not 3 in the friggin morning.
I thought I'd have it all assembled, but the damned trigger install ground my progress to a halt.

Grrrrrrr...


Edit to add:

I decided "screw it, I'm just going to finish this", so on to the next step - install the safety selector.

No dice. That fucking POF 4.5 lb trigger is blocking it from going through. I can work the selector into the lower, but it won't go through the other side because the trigger "housing" that lays in the bottom is protruding up just the teeniest bit - causing the selector to snag on it as I try pushing it through.

I'm pissed. The only thing I can think to do is remove the flippin KNS pins and take the trigger out and file that high spot down.

I'm going to bed. Double grrrrr...

[Nate7667]

Push your hammer down as far as you can in the "cocked" position and it should install with no issue.

[arjohnson]

KNS Anti-walk Pins...

Holy freakin' pain in the ASS to install, Batman!
It must have taken me 45 minutes to figure out a way to get the pins in.

"Apply pressure on the top of the hammer until the hammer/trigger holes line up."

Yeah, OK.

I applied pressure alright. I took some pics that I'll post when it's not 3 in the friggin morning.
I thought I'd have it all assembled, but the damned trigger install ground my progress to a halt.

Grrrrrrr...


Edit to add:

I decided "screw it, I'm just going to finish this", so on to the next step - install the safety selector.

No dice. That fucking POF 4.5 lb trigger is blocking it from going through. I can work the selector into the lower, but it won't go through the other side because the trigger "housing" that lays in the bottom is protruding up just the teeniest bit - causing the selector to snag on it as I try pushing it through.

I'm pissed. The only thing I can think to do is remove the flippin KNS pins and take the trigger out and file that high spot down.

I'm going to bed. Double grrrrr...

The safety is tight, as Nate said push down on the hammer when cocked. They are supposed to be like that because when on safety is on there should be no play in the trigger.

[Emptymag]

I had to use channel lock pliers to "push down" on the hammer to get the pin through.
I put one jaw on the upper edge of the trigger area and the other jaw over the hammer and squeezed. It worked, but I had to install the pins in reverse order. (the "front" one with the tabs first)

I'm assuming it's an issue with those rubber feet and that pushing down is required to smoosh the POF trigger unit down enough to clear.

I'll give that another try but it doesn't make sense that I can push it down any further now that the pins are installed.

[arjohnson]

I had to use channel lock pliers to "push down" on the hammer to get the pin through.
I put one jaw on the upper edge of the trigger area and the other jaw over the hammer and squeezed. It worked, but I had to install the pins in reverse order. (the "front" one with the tabs first)

I'm assuming it's an issue with those rubber feet and that pushing down is required to smoosh the POF trigger unit down enough to clear.

I'll give that another try but it doesn't make sense that I can push it down any further now that the pins are installed.

The hammer should go down a little more.

[Emptymag]

The hammer should go down a little more.

It's not the hammer that needs to go down - it's the black part of the "body" that needs to go down.
The part that lies under the safety selector.

That black part that is protruding to teh far left of this photo. That part lies under where the safety selector passes through.
It's up just a cu#t hair, blocking the selector from going through the other side.



I have to step out for a bit. I'll mess with it later.
If it doesn't work out, maybe I'll put a standard trigger in and try this on another build.