The Continuing Mag Problem, Part2 w/Pics

[Charlie Xray]

Originally Posted by dosei

Here is the odd thing...I can't get the the same thing to happen with mine. My mics, calipers, indicators, and other tools are at work so I can't get any solid numbers tonight. I'll do some measuring on my XD tomorrow to see what the numbers are on mine. Visually though, the case never drops below the bottom of the slide during extraction.

Very much looking forward to your measurements to see if they are significantly different from mine - and anyone else for that matter, especially from those with thousands of trouble free rounds.

CX

[dosei]

I'm looking forward to seeing what mine measures also. Especially since I've put almost 3000 rounds thru mine with zero problems.

[dosei]

Just got done measuring mine.

Max measured barrel drop = .125"
Distance from top of slide to bottom of 45acp case = .635"
Distance from top of slide to bottom surface where mag rounds contact = .760"

So on my gun, it is not possible for the case to drop below the lower slide surface and catch on the next round, which explains why I've shot almost 3000 rounds of various ammo without any issue.



I should add that my XD45 is an early unit, purchased only a couple months after SA began selling the XD45 Service. The only mods that have been done to it are the sights (Tru-Glo TFO's) and cutting the grip down to make it a Compact.

[fritzmeister]

I'm noting all of this. I have the same problem with my 45. It likes to fail to feed rounds.

thanks for the info.

[Charlie Xray]

Originally Posted by dosei

Just got done measuring mine.

Max measured barrel drop = .125"
Distance from top of slide to bottom of 45acp case = .635"
Distance from top of slide to bottom surface where mag rounds contact = .760"

So on my gun, it is not possible for the case to drop below the lower slide surface and catch on the next round, which explains why I've shot almost 3000 rounds of various ammo without any issue.



I should add that my XD45 is an early unit, purchased only a couple months after SA began selling the XD45 Service. The only mods that have been done to it are the sights (Tru-Glo TFO's) and cutting the grip down to make it a Compact.

Fascinating!

How did you get the second measurement - top of slide to bottom of case? I will try to duplicate yours for comparison. Hopefully, a few others will also do these measurements, both those with problems and those without to see if there is a pattern here.

Maybe we are onto something?

Thanks,
CX

[dosei]

Originally Posted by Charlie Xray

Fascinating!

How did you get the second measurement - top of slide to bottom of case? I will try to duplicate yours for comparison. Hopefully, a few others will also do these measurements, both those with problems and those without to see if there is a pattern here.

Maybe we are onto something?

Thanks,
CX

Since the back edge of the barrel sets flush with the top of the slide I just removed the barrel, dropped in a round, and measured with my calipers from the top edge of the back of the barrel to the bottom of the inserted round.

[Charlie Xray]

First off I am beginning to believe the title of this thread is wrong. This is not a magazine issue though new mag springs seem to help. I am beginning to suspect some machining variations and I think it may be barrel related or possibly the rail near the barrel.

These from dosei...
Max measured barrel drop = .125"
Distance from top of slide to bottom of 45acp case = .635"
Distance from top of slide to bottom surface where mag rounds contact = .760"

Here are mine...
Max measured barrel drop = .147"
Distance from top of slide to bottom of 45acp case = .642"
Distance from top of slide to bottom surface where mag rounds contact = .759"

It appears our slide heights are virtually identical, but there are significant differences in numbers relating to the barrels. Let's add a few more measurements and see what happens.



A = distance from the top of the rails to the top of the feed ramp of the frame insert. (CX = L side .247" R side .254" That is a bit disturbing!)

B = Top of the rail to the location indicated. (CX = .118")



C = Height of the slide as noted above. This one will be tough because you can't get calipers in there.



D = Inside bottom of chamber to the bottom of the barrel feed ramp. (CX = .186")

These four measurements plus the max measured barrel drop as the slide comes out of battery, which we will call E, and the measurement from the bottom of the case to the top of the barrel hood taken from a chambered case, which we will call F, from a number of pistols may tell us a lot.

I am asking for help. You are going to need calipers to get these, and I know many of you don't have them, but the measurements need to be as accurate as we can get them. But I sure would appreciate some measurements from others to confirm of deny my theory that there are machining variations in the barrel or the frame insert. Also please indicate if your pistol has had FTF issues or has run flawlessly.

Your help will be much appreciated.

CX

[Charlie Xray]

As requested in a PM I am adding E and F to the mix.



This one is also tricky. To get the measurement for E I jammed the muzzle against a padded object and drove the slide out of battery enough that the barrel dropped out of the locked position to that position it remains in as the slide continues rearward. (This image is a simulation with the slide off the frame for photographic purposes.) I then used my calipers to measure the difference as indicated at the very rear of the barrel hood. You almost need three hands. What this should tell me is do all barrels drop down the same amount? If not then either the barrel lug areas, the frame rail inserts, or the barrel boring are not consistent. Other measurements (A and B) look more closely at the rail insert. And D looks at what I think might be the critical barrel lug measurement. The notch forward of the feed ramp could be the problem, but getting consistent measurements with the way the barrel hood tapers towards the muzzle end may be very difficult. We will resort to that if we can't get a good clue elsewhere.



F is gained simply by inserting a fired case (tighter fit) and measuring from the top of the barrel hood to the bottom of the case. What this will tell me is are there any variances in how the barrels are drilled - some lower than others that might cause the empty to extend below the breech face?

Someone suggested we look at chamber dimensions also, but I am doubtful a chamber could be sized off enough to significantly affect the other measurements without being dangerous and would never have passed inspection.

Depending on what we can gather from these we may be able to draw some conclusions, or they might lead us to look somewhere else. Clearly from the photos and measurements submitted so far, some pistols drop the barrel lower and thus expose the case rim below the breech face to come in contact with the top round in the mag and others do not. The latter seem to be problem-free and the former have lots of FTFs.

BTW, SA did get back to me today with their usual reload disclaimer but offered to examine the pistol for me. I will send it back after I get some info here that hopefully tells me something I can relay to SA, and I do another round of tests with factory loads to prove it happens with those too.

Again, your help is much appreciated. We may be close to figuring out why some XD45s have feeding problems.

CX

[ThumperIII]

You might want to polish up that breech face a bit. It may help a clean brass cartridge head slide up into position easier.

[Charlie Xray]

Originally Posted by ThumperIII

You might want to polish up that breech face a bit. It may help a clean brass cartridge head slide up into position easier.

I have done this on all my 1911s and also their extractor hooks were deburred and polished but not in the XD yet.

CX