mscott Posted January 5, 2017 Share Posted January 5, 2017 I know there isn't much point to it, but wondering if anyone else has built one. I have decided I have no desire to shoot Limited any time in the near future and have a bunch of .40 ammo loaded ahead to burn up, so talked myself into putting one together. I used a New Frontier Armory bolt and Kaw Valley barrel on a lower that takes Glock mags. I had some feeding issues I'm thinking related to the bolt, so had to get that worked out. Seems like the longer and fatter case makes things more critical to be just right. Another problem is that Glock .40 mags swell enough when fully loaded to be a bit too tight in both style lowers I have. I have one lower from Joe Bob's and one from PSA. They are both a bit different, but the PSA has a slightly larger opening on the magazine well. I'm thinking it is going to need opened up just a little more, though. I do have a muzzle brake on it and recoil is not much different from the 9mm rifles I have. Link to comment
gdcguns Posted January 5, 2017 Share Posted January 5, 2017 I built one up in pistol form about a week and a half ago. The only thing I'm missing is the bolt. Can't find one in stock anywhere, so I haven't been able to shoot it yet. I have inserted some loaded mags and I found that my 15rd mags with extensions fit and drop free just fine, but my 22rd factory glock mags bulge just enough to be a little tight. Matrix Arms glock lower Mega Arms SBU billet upper Kaw valley barrel, muzzle brake, and heavy buffer Midwest industries handguard Link to comment
Darqusoull13 Posted January 5, 2017 Share Posted January 5, 2017 JP posted a picture of a 357 Sig PCC one of their smiths made. It might be a one off but you could try to contact them to see if they can help out. Link to comment
gdcguns Posted January 5, 2017 Share Posted January 5, 2017 Just called JP. That's a no-go. Link to comment
gdcguns Posted January 5, 2017 Share Posted January 5, 2017 mscott, What were the feeding issues you had? And how did you remedy the problem? Link to comment
mscott Posted January 6, 2017 Author Share Posted January 6, 2017 7 hours ago, gdcguns said: mscott, What were the feeding issues you had? And how did you remedy the problem? The round was coming out of the magazine and getting jammed nose up half way into the chamber. I think it all boiled down to the bottom finger on the bolt that strips the round from the magazine needed to be shortened. I cut it down by a good .1 of an inch and seemed to be what it needed to feed reliably. Link to comment
Posvar Posted January 6, 2017 Share Posted January 6, 2017 Did the check Quarter Circle 10 for a .40 bolt? Link to comment
gdcguns Posted January 6, 2017 Share Posted January 6, 2017 1 hour ago, Posvar said: Did the check Quarter Circle 10 for a .40 bolt? I called them yesterday. They told me they would have another batch available in about 12 weeks. Also called New Frontier, they said "hopefully in a few weeks." Link to comment
gdcguns Posted January 6, 2017 Share Posted January 6, 2017 Has anyone taken a 9mm bolt and had it milled out for 40? Link to comment
chuckstur Posted January 10, 2017 Share Posted January 10, 2017 Olympic makes an upper that works with any AR lower.... Mine works great but I built a dedicated lower. The 10mm magazines will run long-loaded 40s. Link to comment
mscott Posted January 14, 2017 Author Share Posted January 14, 2017 Here's what I had to do to get it to run. The bottom portion of the bolt used to extend and be even with the rest of the bolt face. Comparing 9mm and .40 cases, I trimmed it about the difference in case length between the two and seems to be exactly what it needed. I polished the face up good after cutting the bottom piece back. I haven't been able to find much info out there on people building .40s other than the factory options. Link to comment
gdcguns Posted January 14, 2017 Share Posted January 14, 2017 Mscott, I found a good deal on a JP 9mm bolt so I bought it. Took it to a local machine shop and they milled out the bolt face to fit a 40. Chambers and fires without any issues. However, I'm having feeding problems like you did. I remembered what you said in your earlier post so yesterday I borrowed a QC10 40sw bolt from a friend whose gun runs perfect to compare it to mine. I had just looked at them this afternoon and saw that they have a different profile on the bottom of the bolt where it strips the round from the mag. So I'm gonna test the qc10 bolt in my gun. If it runs, I'm gonna chop it just like you did. You can see difference in the pic. The qc10 is on the left. Link to comment
mscott Posted January 15, 2017 Author Share Posted January 15, 2017 (edited) Cool. I'm guessing QC10 must have done a little more R&D than NFA. Looks like I was on the right track. I had mine at the range today and the rifle ran great. Edited January 15, 2017 by mscott Link to comment
dennisw1mac Posted March 8, 2017 Share Posted March 8, 2017 On January 14, 2017 at 3:33 PM, gdcguns said: ... So I'm gonna test the qc10 bolt in my gun. If it runs, I'm gonna chop it just like you did. You can see difference in the pic. The qc10 is on the left. Wondering how your test of the QC10 bcg went, if you modified yours, and how it runs now. I too am having chronic feeding problems with NFA bcg, lower & upper. Thanks. Link to comment
gdcguns Posted July 5, 2017 Share Posted July 5, 2017 Dennis, sorry I didn't see your question sooner. I guess I forgot about this thread. I ended up chopping the bottom of the JP bolt to match the QC10 bolt and it helped, but didn't clear up the feeding problems completely. I had to round off the "feed ramp" area of the Kaw Valley barrel and polish it up real smooth. The transition from the feed ramp into the chamber was a very sharp edge from the factory and rounds were hanging up on it. Now it runs like a champ. Link to comment
dennisw1mac Posted July 5, 2017 Share Posted July 5, 2017 (edited) Good to hear. I got help to do the bolt mod and the feed ramp, and mine also runs great now. Your pics were a big help, so thanks. Edited July 5, 2017 by dennisw1mac Link to comment
USCSBarney Posted July 6, 2017 Share Posted July 6, 2017 I have a Quarter Circle barrel and bolt if anyone wants to buy and play. Link to comment
Jerrymarsh Posted July 8, 2017 Share Posted July 8, 2017 https://newfrontierarmory.com/shop/ar-40-standard-40-sw-bcg-glock-compatible/ Link to comment
1911luvr Posted July 9, 2017 Share Posted July 9, 2017 I'm going to be building a 10mm before the end of the year so I can do some pig hunting with it. I love these PCCs and think I'll have more fun hunting with a 10mm PCC than a bolt action!Sent from my iPhone using Tapatalk Link to comment
Makarovowner Posted July 6, 2020 Share Posted July 6, 2020 I built a 40 s&w. Did the 80% receiver. Took a long time but functions well. My magazines swell inserting pretty bad. I had serious feed problems. I reload so I can adjust loads and length plus cast my own bullets. I chose the caliber as I had thousands of casings on hand. I run 175 grain hard cast lead. Feed problem came down to reducing the overall length to right about 1.oo. Why? Cartridge slammed the nose straight into the bottom of the barrel. All rounds not just the first round. Shorter length allows the cartridge to elevate more at the front end. The more I short end the better the feed. Now I cannot just go buy a box of bullets and expect function. That was never my intent but sucks no matter. With the shorter length and a 175 grain bullet the powder charge must be reduced not to compress it. Red dot failed. Not hot enough. Hodgdon clays worked fine on a case filled just to the bottom of the st bullet. Easy way I figured the volume was the measure. But first placed the bullet to the depth on the outside of the case and marked it. Measured by volume until I reached the line evenly. Made a handful and ran perfect. Added flip up sights, a multi position sling, and brass catcher. Shilen ultramatch 16 inch stainless barrel, Anderson match trigger. Think weight is about 7#. I am finding leading in the barrel. Thinking of using liquid alux or perhaps putting some jacketed bullets in the rotation. The barrel supplier did not seem overly surprised at the feed issue and adjusting the length. He said some loads give trouble where others feed without problems all the time. I will be building more. Recoil is surprisingly stout. The buffer I believe is 5.6oz. At this point my mags feed well but getting them in and out sucks. Going to open the magwell slow and careful. Think that will solve it. Hand filing some eased it up but not there yet. Take care guys. Link to comment
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