AR9 SBR build finished, FTF issues gone - Page 1

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[ARCHIVED THREAD] - AR9 SBR build finished, FTF issues gone

Posted: 2/2/2017 1:33:46 AM EDT

I had this PSA based lower AR 9 as a pistol for a while but was getting constant FTFs. I sent the barrel to Rudy @ Macon for him to reshape the feed cone and now the FTFs are gone! Also, a few weeks back my form 1 came back, so voila -

Attached File

PSA AR9 lower
Slick side upper from somewhere that dont remember
Seekins MCSR hand guard
BA 5.5" barrel
Guntec flash cone
Magpul stock & grip

I am having a occasional extraction issue that I still need to figure out though.

Posted: 2/2/2017 2:36:50 AM EDT

[#1]

Looks nice. I never knew Colt mag setups were sensitive to feed cones like Glock setups are.

Posted: 2/2/2017 11:08:45 AM EDT

[#2]

Quote History

Quoted:
Looks nice. I never knew Colt mag setups were sensitive to feed cones like Glock setups are.

View Quote

They shouldn't have issues as long as the feed cones was 'to spec' to begin with.

I seem to recall a thread or a few about BA barrels having feeding/feed cone issues. I thought someone also said they may have made changes not that long ago?

No dig at BA, but there are a lot of players in the market making 9mm parts these days - not all do it to spec, not all do it correctly, not all know what they are doing...

Posted: 2/2/2017 2:26:13 PM EDT

[#3]

To be fair to BA, the PSA lower does set the mag farther back than a normal mag block does by 1/2" or so. There is a small "feed ramp" between the mag and barrel that is an add in piece. It may feed just fine on a normal mag block AR 9, but I don't like the look of a full size magwell with a little size colt mag. I bought the PSA lower because they cut the extra magwell portion off so it looks more like a real 9mm subgun.

Posted: 2/2/2017 6:25:03 PM EDT

[#4]

Quote History

Quoted:
To be fair to BA, the PSA lower does set the mag farther back than a normal mag block does by 1/2" or so. There is a small "feed ramp" between the mag and barrel that is an add in piece. It may feed just fine on a normal mag block AR 9, but I don't like the look of a full size magwell with a little size colt mag. I bought the PSA lower because they cut the extra magwell portion off so it looks more like a real 9mm subgun.

View Quote

Here's a good reference thread that has two people with barrel feed issues. There are others if you search. Make a mental note of the brands and how often they recur. https://www.ar15.com/forums/t_3_15/701894_FTFs_on_9mm_colt_style_lower.html

In that thread, Rudy says he's done several hundred feed cone modifications as of 9/2016. THAT'S A LOT! It would be interesting if he were to share which barrel brands and how many of each he has worked on, so everyone could understand if there was a trend, even if it's just anecdotal.

Posted: 2/2/2017 7:05:14 PM EDT

[#5]

OP (ar15eric):

question: with the FTF's, are you using Metalform-style mags (e.g. Colt original, Brownells, Metalform), or ASC-style (e.g. Midway's AR-Stoner, ASC)? i didn't see that mentioned, and couldn't tell from the pic.

just wondering.

i took my newly completed 9mm out, BA barrel, Hahn dedicated magwell block, would only work with my Brownells mags. i had feeding problems with my ASC mags, which i do intend to further evaluate. i did have to file a little on the feed lips to get the ASC mags to clear the channels on the bottom of the bolt, and had to file a little on the orange follower so that it wouldn't hang up on the rear edge of the mag block feed ramp.

thanks.

Posted: 2/3/2017 12:56:23 AM EDT

[#6]

Quote History

Quoted:
OP (ar15eric):

question: with the FTF's, are you using Metalform-style mags (e.g. Colt original, Brownells, Metalform), or ASC-style (e.g. Midway's AR-Stoner, ASC)? i didn't see that mentioned, and couldn't tell from the pic.

just wondering.

i took my newly completed 9mm out, BA barrel, Hahn dedicated magwell block, would only work with my Brownells mags. i had feeding problems with my ASC mags, which i do intend to further evaluate. i did have to file a little on the feed lips to get the ASC mags to clear the channels on the bottom of the bolt, and had to file a little on the orange follower so that it wouldn't hang up on the rear edge of the mag block feed ramp.

thanks.

View Quote

I've used metalform and CPD mags. The performed the same.

Posted: 2/3/2017 1:07:15 AM EDT

[#7]

I also had issues with Balistic Advantage and my Glock mag setup:

https://www.ar15.com/forums/t_3_15/695315_.html&page=1

Feed cone was way too steep.

I also had to send it to Rudy to fix it.

I now use Faxon because of their more shallow feed cone:

http://www.firearms4less.com/2224-thickbox_default/faxon-9mm-ar15-barrel-85.jpg

Posted: 2/3/2017 9:24:30 PM EDT

[#8]

I sent my Green Mountain to Rudy to fix the chamber, so apparently 9mm barrels are just really confusing. (Except to Rudy. :)

Posted: 2/4/2017 2:22:16 PM EDT

[#9]

Quoted:
I had this PSA based lower AR 9 as a pistol for a while but was getting constant FTFs. I sent the barrel to Rudy @ Macon for him to reshape the feed cone and now the FTFs are gone! Also, a few weeks back my form 1 came back, so voila -

https://www.AR15.Com/media/mediaFiles/427565/IMG-0104-138454.JPG

PSA AR9 lower
Slick side upper from somewhere that dont remember
Seekins MCSR hand guard
BA 5.5" barrel
Guntec flash cone
Magpul stock & grip

I am having a occasional extraction issue that I still need to figure out though.

View Quote

You did not mention which bolt you are using.

You can twist the extractor to get it to line up tangent to the case. You have to remove the extractor and clamp it in a vice. Use a pair of needle nose pliers to grip the front end just behind the claw and twist it. Hope this helps.

If you are having FTE (failure to eject) issues the ejector can be twisted so the front is closer to the bolt center. This can be done with the ejector in the lower.

Posted: 2/4/2017 9:03:40 PM EDT

[#10]

Quote History

Quoted:

Here's a good reference thread that has two people with barrel feed issues. There are others if you search. Make a mental note of the brands and how often they recur. https://www.ar15.com/forums/t_3_15/701894_FTFs_on_9mm_colt_style_lower.html

In that thread, Rudy says he's done several hundred feed cone modifications as of 9/2016. THAT'S A LOT! It would be interesting if he were to share which barrel brands and how many of each he has worked on, so everyone could understand if there was a trend, even if it's just anecdotal.

View Quote

Just to expand on this, the number of 9mm AR barrel makers has exploded in the past several years. I think that a bunch of the "new kids" aren't paying attention to the feed cone on their barrels, leading to all these problems. Rudy's experience, as kevins_garage points out, seems to support this.

Further, my 10" 9mm barrel, which I got from Spikes about 7 years ago, feeds fine with my Rock River Colt-style magazine block (and all of the mags I use with it), AND the same upper runs fine on my QC10 Glock lower, without any changes at all. 9mm ARs didn't change radically in 7 years, but the number of 9mm AR barrel makers sure has!

Posted: 2/5/2017 1:13:24 AM EDT

[#11]

Quote History

Quoted:
You did not mention which bolt you are using.

You can twist the extractor to get it to line up tangent to the case. You have to remove the extractor and clamp it in a vice. Use a pair of needle nose pliers to grip the front end just behind the claw and twist it. Hope this helps.

If you are having FTE (failure to eject) issues the ejector can be twisted so the front is closer to the bolt center. This can be done with the ejector in the lower.

View Quote

I'm using the PSA hybrid bolt.

Posted: 2/7/2017 1:51:41 AM EDT

[#12]

I have the same lower, the installed PSA bolt catch was much too long and hit the ammo in mag causing jams, I had to file a bit off. It has been 100% since thru 350 rounds.

Old Rock River barrel
RRA Bolt ramped by Adco back in the day
Metalform mags

Posted: 2/8/2017 1:25:43 AM EDT

[#13]

Quote History

Quoted:
I have the same lower, the installed PSA bolt catch was much too long and hit the ammo in mag causing jams, I had to file a bit off. It has been 100% since thru 350 rounds.

Old Rock River barrel
RRA Bolt ramped by Adco back in the day
Metalform mags

View Quote

I had to file down the bolt catch as well. Luckily, before I even had a chance to shoot it someone in this forum had a picture of that so I took care of it before my first range session.

Posted: 2/16/2017 1:31:09 AM EDT

[#14]

So I took the rifle to a steel match last weekend shooting over 200 round and had only one issue. It seems like it might be working itself out?

[ARCHIVED THREAD] - AR9 SBR build finished, FTF issues gone

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