CAR15 SD.

A glorious shoot today. I think I may be settling in on a Spikes variable pitch buffer spring with a Kynshot 5000A5 in an A5 buffer tube.

That seems to run around 620. When I plugged in a Tubb lightweight the ROF dropped to 585 - a bit too slow for my liking.

I may try a few clips off a Tubb 556 and see how that does. The full 556 Tubb is a bit strong to consistently FRT with this HSL 115.

The 5000A5 really does push most of the SD gas down bore and out the muzzle - quite awesome!

FM9 7” with Integrated Folding Lower, plus obsidian 9, zentinal holo, and applesauce charging rod and handle… atrius SS

ISU at home?

Please see comments for more detail

9 pictures. Original 1st gen Colt Unramped bolt provided for measurement/documentation by a fellow Redditor and will be returned shortly. It arrived with what apperars to be a 3rd gen model ramped Colt bolt as well for comparison purposes.

This is, to the best of my knowledge, a very early production 1st generation Colt original 9mm AR 635 bolt. If so, it's a bit of a unicorn, so I wanted to share pictures before I had to send it back. I'm planning on making a video about it, covering some of the information below.

The fact that it does not have a lateral groove in the "reverse ramp" just below the firing pin should mean it was produced before the Henry Tatro/Colt patent for a “Safety Device Preventing Conversion To Full Automatic Firing” that used a notched bobbed hammer to stop the gun from firing if the disconnector was tampered with. The patent was applied for on September 25, 1985. and the patent approved (U. S. Patent No. 4,658,702) on April 21, 1987.

Colt started producing the 9mm 635 SMG around 1982, about 3 years before they applied for the patent.

The "2nd gen" grooved bolts were used in both military and civilian models, but the bobbed, notched "9mm hammer" for conversion prevention was only installed in civilian models. The military models used a standard M16 trigger set. This "1st gen" bolt would have only been used in early military models.

Note the "reversed ramp" under the firing pin. This was a feature of the 1st and 2nd gen bolts and known to be very abusive on the hammer pin, often causing them to snap. This is how 9mm AR's got the reputation for breaking hammer pins. Instead of ramping the bolt to fix the problem, and getting rid of the "Safety Device..." baloney, Colt started using stronger stainless steel pins that egged out the holes in the receiver and still snapped. Later, Colt did start ramping the bolts (3rd gen) and abandoned the "Safety Device..." idea.

This reverse ramp may (my hypothesis) have been used as an attempt to create a leverage disadvantage for the bolt when cocking the hammer, much like the firing pin stop on an old Colt 1911. If the 1911's firing pin stop has a very shallow curve at the base, which most older Colt 1911's did, it requires more recoil pressure to push the hammer out of the way when the slide reciprocates back. Applied to a blowback 9mm, this may help reduce the bolt velocity by adding a leverage disadvantage over the hammer spring when cocking the hammer compared to a ramped bolt.

It makes sense that Colt would try to apply this technique from their 1911's to other platforms.

I tested 3 bolts in an AR with a force gauge, standard carbine spring, standard milspec hammer spring:

- Gen 1 Unramped Colt bolt: 12.2lbs. of force to cock the hammer

- Gen 3 Ramped Colt bolt: 11.8lbs. of force.

- Modern Outerwild bolt: 11.2lbs. of force.

Almost all modern bolts are ramped, allowing the bolt to more easily reset the hammer.

I took a number of measurements and will be adding the data to my bolt database. An updated chart will be uploaded soon.

I finally ran the new PCC build this week and it performed much better than I expected. I thought I would have to adjust my buffer set up but that did not happen.

I’ll try to run the D50 next week to see if I encounter any issues.

Aero EPC Upper

NBS Suppressor series rail 9.25”

Novox Research X-SD barrel kit 4.3”

Aero EPC lower (shelf cut)

GMR SS

KVP 10oz Buffer

Kynshot Spacer x2

JRC 8” buffer tube

Tubbs lightweight buffer spring

IDL Industries Gen 3 bolt

Davidson Defense titanium 9mm firing pin

Rex Silentium MG7K 358

For a PCC.

New stuff....

Basic Magpul stock

3d printed mag sleeves for 5 33rd glock mags

3d printed suppressor, material is pla+ (tested with +p ammo, it is functional)

Old post......

Fm9 paratrooper upper and ambi lower with a5 tube

Fm g.b.r.s. 9.5oz buffer

Macoon 10.5 barrel

Angstad arms 3 lug comp and qd blast mitigator

Fab defense grips

Magpul sling and qd mount

Magpul mlok rail covers

Eotech exps2-0 on unity riser

Streamlight protac 2.0 rm and unity switch

Unity hub with fixed front sight and light mount

Utg a2 rear sight

Partisan 3 position frt (maybe, not 100 on who made it)

I blacked out all the logos (i missed one on the riser)

Old note......

This took about 3 months to get everything together and sort out all the fitting. Only thing i still want to add is a law tac folder.

New note.....

The 3d printed suppressor i dont expect to last long under any heavy use. All i can say is it didnt blow up in my face after 1 shot of +p ammo. Reports of light use on these without reinforcement has been positive. For the 3 dollar it cost to print i was genuinely surprised at the quality. Credit to mjm3d on makerworld.

I have an Aero EPC9 and installed the buffer kit thst came with it. Im missing the buffer spring but I do have the 7.7oz weight. What would be a good buffer spring to get for it? I know the kit says a warning length .308 spring, but would a 5.56 spring work?

Freedom Ordinance FX9

* Vortex cantilever 30mm ring mount

* Vortex Strikefire II red dot

* KAK Shockwave Blade Brace

* Jungled Glock OEM 33 round magazine/ETS 31 round magazine

* Magpul AFG-2

I'm new to the AR9 platform, so forgive me if this is a "dumb" question. I am predominantly a handgun shooter, and polishing ignition components usually leads to much nicer trigger pulls and resets. I have a BM-9 that I just did a few upgrades to. One of those upgrades was an Elftmann Tactical Pro trigger. I went to the range with it for the first time, and my trigger wasn't resetting. I figured out it was because the trigger pull weight screw was set too light. There is a surface that the trigger and hammer engage together, and it looks, feels, and sounds a bit rough. My brain is saying, if you polish those two surfaces, you will get a smoother reset that will require less force, thus allowing you a lighter trigger pull, or at the very least a smoother reset. I have circled the area that I am talking about polishing. One picture is with the trigger not reset because the set screw was too light, and the other is with it reset. In the picture with the trigger reset, you can see the surface is kinda rough and is an area where there is going to be wear. Is this a terrible idea?

Thinking about acquiring an AR9 pdw, and I'm wanting something with near Glock levels of reliability. I can't afford the ammo costs associated with frt nonsense. So what's really reliable in regular semi auto fire rates of fire?

AR9 getting a lot of action recently under the thermal 🤌🏼

I asked previous about potentially purchasing a Shield Arms SA-9 foldable pistol, but some members here pointed me to Foxtrot Mike and I ended up getting a MIKE9 SUPER PREMIUM FOLDING AMBI 7'' REAR CHARGE PISTOL W/ RMB.

What would be recommended upgrades? I’m potentially looking at better trigger, better pistol grip, upgraded blast diffuser/comp/muzzle brake (no suppressor), green dot (RMR footprint, I already have a 0.75” riser)? I already have a SBA-5 as well.

Any suggestions for a relatively shallow or flat light? I’m also looking for matching Glock magazine extensions that brings the mags to 20 rounds (can’t be more).

Anything else that would help with either recoil or improve the overall experience?

I saw that Kentucky Tactical in his YouTube video has a Kynshot buffer. Does that help with the RMB system?

Thanks in advance for the input.

Going to the range tomorrow to get her sighted in, figured I'd bring her friends along also....

So I have an ar15 lower with a frt installed, how can I make a 9mm mag adapter in the ar lower run frt with a 9mm upper.

I was originally set on builiding my own AR9. After already having built an AR-15, I thought it should be no big deal. There were a few requirements though. Not longer than 23.5 inches, should take magazines with close to or exactly 20 rounds (but not over) and needs to be foldable.

After I found Shield Arms foldable lower receiver instead of buying a folding adapter that adds to the overall length, I ran into their fully built SA-9 folding pistol. It seems like good parts were used and an overall balanced and well built piece. More importantly: it matches ALL my criteria right out of the box. The price of $1500 plus tax seems to be on the high side though at first glance.

https://shieldarms.com/sa-9-flr-75-folding-pistol-9mm

My questions are: Any opinions? Does anyone have experience with it? Pros/cons? Alternative suggestions?

Thanks in advance.

Is it worth getting a folding adapter, or are they destined to fail?

I just had this itch.

• Bear Creek AR 45 pistol
• Blackwood Trading furniture and stock (this company is a PITA)
• Blind Squirrel Cutt's Compensator
• Sig red dot sight
• Kerr Sling

Sure is fun to shoot. Loud as hell with that compensator. Definitely starts some conversations at the range.