Colt Quarter Circle 10 build.

[Aircooled6racer]

Hello: This is the start of my Quarter Circle 10 AR 9mm Colt mag build. Just to let everyone know I am not sponsored by Quarter Circle 10 or by any of the other parts that I used in this build. I will start by saying I am very pleased with most of the choices of the parts that I used in the build and the build is finished at this point. I tried various parts and ended up with what I thought was the best for me. I did have some bumps in the road along the way and hopefully now have them all sorted out. Here are the first couple of pics of the Quarter Circle 10 Colt magazine lower. It has a larger magwell opening than using a AR15 magwell insert and reloads faster for me. Thanks, Eric

[Dr Mitch]

Are the Colt mags particularly excellent?  Just curious why you went with that over Glock mags.

[TRUBL]

I have this very lower......love it, you did not go wrong.

 

As to answer your question Dr. Mitch......I asked a while back what was better (colt/glock)........pretty much got a 50/50 response, so I did both.

 

I must say......I give the nod to the lowers that take the colt mag's.....not that glock lowers are bad, I just found that the mag availability was there and plentiful for the colt. I do like the fact that it is a true double stack and the ramp in the lower really works well. I also have had zero issues with any feeding of ANY ammo that I have fed is so far.

 

One thing that I did notice on the MAJORITY (not all) of the glock lowers is that their is no feed ramp on the lower.....no feed ramp and there is a .200" gap between the front of the mag and back of the barrel......I've had issues feeding 115's. Look at a Glock pistol sometime......no gap. I did design and will be offering a retrofit ramp that will fit into the uppers that people use on their glock lowers in the near future.

[Aircooled6racer]

Hello: I went with the Colt mag lower since I had a insert for the Colt mags and it worked out well. The lower also has a built in feed ramp which I liked over the Glock style lowers at the time. I also found Metalform Colt mags to be inexpensive. I also knew base pads would be available as well. The last reason was that the mags go in straight not at an angle like a regular AR15. Thanks, Eric

[Aircooled6racer]

Hello: Still testing this one out. I went with a Wilson Arms 16" barrel, JP bolt, JP silent buffer setup & also standard buffer setup, Matrix hand guard, Hiperfire 24C & Jard 2lb triggers, C-More 6 MOA railway, Raptor charging handle, Mission First stock, Bravo grip, KNS pins, Seekins bolt release, Strike take down pins, Rock River safety, Oden mag release, Taccom magwell, Magpul buffer sling mount. I'll take some pics soon. Will see how it runs this weekend. Thanks, Eric

[SergioSF]

Already sounds awesome. Looking forward to the pics and range report!

[Aircooled6racer]

Hello: Here is what it looks like so far. I think I may be done with it for a little while but still may try some different things to see what works best for me. Thanks, Eric

Edited February 14, 2017 by Aircooled6racer

[ctay]

Looks good Eric. Does the comp work you think?

[Aircooled6racer]

Chris: I have made quite a few comps over the years for 9mm rifles. This is a combo of all of them and I think it is a combo on how it works. I think the weight does more than the actual ports do. Load and buffer tuning does even more than the comp does. With 9mm blowback and a 16" barrel there is just not enough gas generated to work the comp for full effectiveness. If you had a shorter barrel like an open pistol then you could get something out of it. I do know that it is redirecting the gasses since I am getting a buildup of powder residue on the comp. I am shooting 130-135PF loads with 147's so it is soft shooting already and flat. I can can do 0.14 splits at 10 yard A zone head shots all day long with my setup right now. If I could run faster and see better I may even be faster on the stages. Thanks, Eric

[Aircooled6racer]

Hello: Just and update since I am shooting both a Colt and Glock Quarter Circle 10 lowers now. The Glock lower does seem to need a magwell like the Colt lower does. Both are running great with 147 grain bullets at 133-137PF. I upped it a little to help with ejection when the gun is held a weird angles around barriers or walls. The Colt lower seems to feed a little smoother than the Glock lower for some reason. I think it maybe the feed ramps or magazine style. Both work well with 1.145" OAL ammo and shorter factory stuff if I change out the buffer setup. If you are thinking of building a PCC I would start with good parts. I have a seen a couple now that just don't work well and the guys get frustrated very quick. Nothing worse than a gun that doesn't go bang! Thanks, Eric

[bmiller]

I agree it needs a Magwell.  Cutting this design out of aluminum next.

[Aircooled6racer]

Hello: The Colt lower does need a magwell but the Glock lower seems to work without one just fine. The tapered Glock mag just guides itself in there better than the Colt mags does for me. I also reload them different. I drop the rifle onto the Colt mags and insert the Glock mags into the rifle. Others may have different results with the lowers they are running. Thanks, Eric

[OPENB]

Does the QC10/Colt have last round bolt hold open? 

[Aircooled6racer]

Hello: The QC10 Colt lower does have last round bolt hold open. It works 100% with Metalform mags. It also works 100% with Metalform mags with Taylor Freelance base pads on the 32 round mags. I never run it dry in a match but often do when playing around with it. Others that have shot it have as well. Thanks, Eric

[fedupflyer]

Does your QC10 Colt build leave scratches on the brass from the feed ramp?

Mine does and I am thinking about polishing it.

[1911luvr]

Does your QC10 Colt build leave scratches on the brass from the feed ramp?
Mine does and I am thinking about polishing it.

Are you sure it's the feed ramp and not the bottom of the bolt causing it?


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[Gman57]

What do you have in to the build less the red dot? Any tricks or tips in building a 9mm vs 5.56?

Thanks for sharing

G

[fedupflyer]

On 3/21/2017 at 10:38 AM, 1911luvr said:

Are you sure it's the feed ramp and not the bottom of the bolt causing it?


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At this point no.

Based on the the scratch marks are apporx the same circumference as the feed ramp, I am leaning toward the feed ramp being the culprit.

More testing is required.

[bluesman2a]

Eric,

 

I just got done putting my QC10 Colt build together last night, I opted for a Gibbz side-charging upper with a KVP 16" barrel and JP bolt/SCS. Thanks for all the great info here! 

Odd question here: on your lower is/was your mag release sticky? In looking at mine there seems to be some binding on the side that has the flat release plate. I tried some polishing and sanding to knock down any rough edges, but it seems to still be an issue. I didn't play with it too long before I had to stop. I haven't shot it yet, but I can see this will drive me nuts. I also polished the mag release bump that rides inside the magwell, it's better now, but still not great. Going to try another mag-catch later, but thought I'd ask..

 

.  

[Aircooled6racer]

Hello: My mag catch is just fine the way it is. I didn't have to mod the catch in any way. I did add the Oden Works extended release button. I think the catch is an old DPMS unit I had laying around. Your QC10 build looks great how are you liking the side charger? You shooting River Bend this weekend or South River next weekend? Thanks, Eric

Edited March 24, 2017 by Aircooled6racer

[Gman57]

3 hours ago, bluesman2a said:

Eric,

 

I just got done putting my QC10 Colt build together last night, I opted for a Gibbz side-charging upper with a KVP 16" barrel and JP bolt/SCS. Thanks for all the great info here! 

Odd question here: on your lower is/was your mag release sticky? In looking at mine there seems to be some binding on the side that has the flat release plate. I tried some polishing and sanding to knock down any rough edges, but it seems to still be an issue. I didn't play with it too long before I had to stop. I haven't shot it yet, but I can see this will drive me nuts. I also polished the mag release bump that rides inside the magwell, it's better now, but still not great. Going to try another mag-catch later, but thought I'd ask..

 

.  

Good looking Carbine there!!!

[bluesman2a]

21 hours ago, Aircooled6racer said:

Your QC10 build looks great how are you liking the side charger? You shooting River Bend this weekend or South River next weekend?

 

Thanks for the kind words all.

 

I haven't been able to do more than shoot a couple of test rounds, and play with the controls in dry-fire sims, but it's a little different. I can see where it would be nice for clearing jams in that you just tip it far right and rack. In practical application, I haven't run it enough to have an opinion yet. 

 

As for matches, I'm still focusing on steel matches at this point. I'd like to look at more action shooting at some point. With PCC, is there just a requirement for a sling and holding your mags, or is there other gear necessary to shoot a match? 

[Aircooled6racer]

Hello: No sling needed and two mag holders will work on a belt. Get some Taylor Freelance base pads for those Colt mags and you are good. I also use 20 round mags for mag changes on classifiers but you can use the big sticks also. Thanks, Eric

[twowheels]

Aircooled, are you referring to the Taylor Freelance Uzi +10 extensions? 

[Aircooled6racer]

2 hours ago, twowheels said:

Aircooled, are you referring to the Taylor Freelance Uzi +10 extensions? 

Hello: No the Colt SMG base pads from Taylor Freelance. Thanks, Eric