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9mm AR's

Thought I would add some pics of the PSA bolt...
 

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Another bolt pic, the buffer and look down the mag well...
 

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My PSA bolt is the older Colt style.

Looks like it has a wider rib on the bottom.
 
How difficult would it be to change that ejector? I've not figured out why the 9mm's use a fixed arm, instead of an ejector pin, like the standard AR bolt. Is case length the issue? Is the fixed arm ejector a common fail point?
 
How difficult would it be to change that ejector? I've not figured out why the 9mm's use a fixed arm, instead of an ejector pin, like the standard AR bolt. Is case length the issue? Is the fixed arm ejector a common fail point?

Looks like just knocking out the roll pin.
 
Here are a few more pics which is all I have at the moment. Let me know if you want pics of another part of the gun. Note that these are pre-range outing and the parts got good 'n dirty since then... :) I believe the buffer is solid steel and I thought I weighed it but can't seem to find the measurement right now... :rolleyes: ;)
 

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How difficult would it be to change that ejector? I've not figured out why the 9mm's use a fixed arm, instead of an ejector pin, like the standard AR bolt. Is case length the issue? Is the fixed arm ejector a common fail point?

I'll have to look at the bolt the next time I have the gun out. The ejector looks fairly stout to me. (see pics I added above) It seemed to consistently kick empty cases about 4' to the right and 1' back (approximately). There was no notable damage or scraping to the cases despite the "narrow" ejection port.

IN-POST UPDATE: you had me thinking about case issues so I went and looked at some empties both from the AR-9 and the G26 we used. There is just a tiny bit more "scratching" on the rim from the extractor from the AR-9 compared to the Glock. I may give it a mild polish to cure that if it doesn't "cure" itself eventually. The primer strikes are about the same depth but of course the Glock leaves that rectangular "window" around the dimple. There was no noticeable case deformation.

Looking at the barrel/loaded chamber pic above, you can see the case head sticks out a little bit but looking at the spent cases, there was no evidence of bulging to the naked eye. The chamber did leave an "impression" and I may give it a polish while I'm doing the extractor. I would be curious what a +P or +P+ round would look like afterwards but I don't have any on hand...

PS: note that there is no "last round hold open" (LRHO) on this gun although the bolt release will hold the bolt open if done manually. In looking at guns that have it, it seems like a very spindly mechanism and I've heard stories of them failing. I added some PSA stock pics from my archives. The first shows set screws holding the ejector in (to answer your question) and the second and third show the LRHO lower.
 

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So, I may have pulled a Homer Simpson D'oh moment. Ordered the Mod 2 Tailhook the other night. And just tonight noticed SB Tactical offers an adjustable brace, that from what I see can be put on a mil spec carbine tube, instead of the Tailhook proprietary tube. At 70 bucks cheaper.
 
I have the gen 1 tailhook on my 9mm firearm. It is very good quality. I understand how you feel about the extra money, but wait until you get it in hand and get to look it over. I think you will be very happy with it.

Plus, with the tailhook having a proprietary tube, can't anyone accuse you of "quickly swapping out for a buttstock" kind of raw deals since they're made differently.

A lot of lawyers like to use the "intent" and "readily changeable" verbiage to show just how easy it is to do something that you weren't doing.
 
Don't really foresee myself needing to defend having a brace on my pistol. A brace is a brace IMO. The design of the Tailhook is a little quicker though, and the ingenious cantilever theory makes perfect sense. So in the long run I'm sure I'll be more than content with the rugged aluminum construction, and ease of use of the Tailhook. Although the slap of the aluminum may sting a tad more than than the flexible materiel of the SB, should I attempt some type of cheek hold shooting style.
 
Seeking advice. I'm having recurring failure to feed, last round, only with hollow point ammo. A full mag of hollow point will run fine until last round, and last round regardless of loading will feed fine if it's FMJ. have tried various magazine brands, with the same result. KAK mag block, colt pattern. Tried with ASC, C-products, and Promag
 
my guess (seriously) is the taper of the bullet.

When another bullet is seated below it, slightly changes the angle that it feeds and the follower isn't angling it up as much.

Is it a round nose hollow point? Or a long tapered nose hollow point, kind of like a wadcutter hollow point?

9mm was designed with a round nose, so anything other than round nose may change the geometry of the feed angle.

Can you tell how it's failing to feed? Getting hung up on the side of the mouth of the chamber? Somewhere else?

One alternative would be to load a standard round nose bullet in the mag first and the remaining be HP"s, but that's not so much as a solution as it is a band aid.
 
I've used HST, and IMI die cut hollow point. I'm not real sure how you would classify them. Round nose maybe? They all catch the top of the chamber. About the 11:00 position. Messing around with it last night, I figured out once the bullet seats in a ways , from repeated jams, it will start functioning more better. Obviously I didn't fire these rounds, as I don't know what kind of pressure spike the setback would cause
I had thought of just loading with a round nose as the last round, and that would be okay so long as I keep magazines pre loaded for whatever situation. I would like to get 100% reliability though
 
I am kinda with John A. Ask yourself, whats different about the what happens to the last round compared to the others?

I would take a look at the follower. Thats going to have a different effect on the cartridge. Easy cure might be clean and polish the top of the follower. All rounds except the last slide on top of the next cartridge. The follower, if rough may be resisting the forward movement of the cartridge enough to hang it up.

I doubt the bullet shape would be a big issue. If the gun feeds ok with all the other rounds, why not the last?
 
I understand what you mean. I want my guns at 100% too.

Let me ask you a question. Does your feedramp have guide grooves in it where the bullet would kind of ride in the groove?

I noticed two distinct "tracks" in the fouling from a lack of better term where the bullets were contacting the feed ramp and being slid into place.

What I did was take a really small round file and filed only where those little tracks were to act as a guide.

I wasn't having any feed problems before or after filing the little groove, but I don't see how it would hurt anything either.

Here's a quick snapshot looking down at my feedramp to maybe help describe it a little better.

And if you notice, the grooves are not both at the same angle in relation to the chamber too. The right round does in fact feed more to the 11 o'clock direction.

It wouldn't hurt to try a different kind of hollowpoint in the gun. Especially if feeds other round nose.

I was also going to mention the follower like Tranteruk. If you can look at how the last round sits load up 2 more rounds so you can see how the right round sits and compare the two, will probably give your answer what you need to do. You may have to file some of the follower so the bullet seats more like the ones that are feeding are.

But you'd also need to do the same to all the other magazines you said you own and tried.

I suggest a different hollowpoint and see how that works out.


feedramp 002.JPG
 
Pretty sure the mag block has guides in it. Doesn't mean they don't need massaged a little bit though. Maybe take a little bit of the angle out, get the round into the chamber a bit flatter. I hadn't thought about working the mag followers. Good advice guys, thanks.
 
The followers may not be the main issue. Especially if you are using multiple magazines.

But if you can look to see how that right round is seated while there are still bullets stacked underneath and compare to how it seats directly on top of the follower itself, may change the geometry just enough to case it to nosedive into the face of the chamber rather than glance off and go into the chamber.

I would rather not modify all of the magazine followers. That sounds counter-intuitive.

I seriously would try a different HP bullet before making any physical changes to the gun.
 
I understand the logic of trying different ammo, but the HST is what I run through the handguns, and the Hi point. And in a "situation" I would like to know the gun will run whatever I can find to put in it. Paranoid, I know. And I may try other ammo. Just have to get around to getting some. I'm not afraid to make some minor modifications for "ammo blind" reliability
 
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