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*10mm* Smith & Wesson M&P 2.0
- Thread starter mark40sw
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(SORRY this is long)
I have a hypothesis on this of why I ONLY have trouble with the 200 grain hard cast cartridges.
It'll require more testing to confirm.
I've been doing some research and have found others who have these that when they shoot the 200+ hard cast rounds the magazine falls out.
One guy on another forum even followed up with S&W with new magazines and even a replacement pistol.
He continued to have the same magazine fall out problem with hard cast 200-220 grain, but other smaller bullet loads worked OK.
MY HYPOTHESIS:
I took 3 magazines and partially loaded them with
Doubletap 200 grain hard cast,
Underwood 180 grain JHP, and
Underwood 155 grain JHP.
respectively.
With each magazine, I pushed the cartridges down and slowly let them come back up.
I noticed that the cartridges all pushed forward in the magazine.
With the Doubletap 200 grain hard cast, I noticed that the wide front of the bullet pushed right up against the opening in the magazine that the magazine catch holds the magazine and left little if any room for the catch.
With the Underwood 180 grain JHP, the bullet end left more space for the catch to hold the magazine.
With the Underwood 155 grain JHP it left even more room for the catch to hold onto the magazine.
I ALSO noticed with the 200 grain hard cast, that when it dropped the magazine out, IT DIDN'T do it on consecutive rounds.
which makes sense as the cartridges pass by the catch opening every other shot.
I did a quick picture of these 3 cartridges to show that the 180 JHP and 155 JHP taper more to a smaller end then the bigger and flat nose of the 200 grain hard cast.
And thus leave leave room at the catch opening to not push the catch out as the cartridges move by the opening.
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I'd agree with your assessment .... there's almost no taper to that hard cast bullet !
I think I read something similar about the new Sig 10mm mags and certain loads. Will have to see if I can find the thread.
Edit, OK found it and the issue sounds even more serious on the x10 if this internet post is to be believed: https://www.sigtalk.com/threads/p320-xten-im-heartbroken.425800/
In any case, sounds like you have diagnosed it.
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Have you tried a plunk test with the ammunition you have problems with?
Maybe they have the wrong COL for that type of bullet. I know the 220gr+ have a longer COL and that causes problems. If you load your own you can get around that by doing a plunk test and working up a load.
In the case of my M&P 10mm magazines, there's space for the cartridge to move front to back slightly.
It's just that the flat front end of the Doubletap 200 grain hard cast rounds are WIDER ON THE END and come right up to the edge of the notch in the magazine that holds it in.
When I compare the width of the end of the Doubletap 200 grain hard cast with the Underwood 200 grain hard cast bullet, the Underwood 200 grain hard cast bullet is not so wide on the end.
(SEE PICTURES BELOW)
I don't believe I have any Underwood 200 grain hard cast rounds to test this theory, BUT I believe they may work OK as they aren't so wide on the front end.
EVERYTHING else I've shot through this M&P 10mm 4.6" has worked flawlessly.
Yes, I just did the plunk test on all three of the cartridges and they pass with no problem.
I believe the problem is caused by the Doubletap 200 grain hard cast bullet being so wide on the front end to interfere with the catch that holds the magazine in, as all other rounds have worked fine.
I see that the front end of the Underwood 200 grain hard cast bullet front end tapers down narrower than the Doubletap.
This extra width could be what causes jams too, as the other rounds work flawlessly.
(SEE MY PREVIOUS POST WITH PICTURES THAT COMPARE BOTH)
This theory will be tested as soon as I get some Underwood 200 grain hard cast rounds.
As luck would have it, I picked up a 4.6" with thumb safety last night for a good deal. I have a variety pack of ammo to test out and see what will function and shoot straight enough for deer season.
Eventually, I'll end up making my own reloads likely using starline brass, and Hornady 180gr or 200gr XTP's. I already have all the reloading dies and setup from years ago, but now just need a pile of brass and bullets.
Eventually, I'll end up making my own reloads likely using starline brass, and Hornady 180gr or 200gr XTP's. I already have all the reloading dies and setup from years ago, but now just need a pile of brass and bullets.
Attachments
UPON FURTHER TESTING I've found something else that could explain some of the reasons the magazine falls out.
With a full magazine of Doubletap 200 grain Hard Cast rounds, I pushed in on the opposite side of the Magazine Release to make sure it didn't move.
This time when firing, the magazine didn't fall out, and the round either was chambered, fired and brass ejected, OR it jammed with the wide front nose of the bullet jammed against the top opening of the chamber.
IN looking at the picture, I believe the magazine could also be forced out from the DOWN leverage on the magazine of the slide closing, and the rear of the cartridge being pushed down by the force of the slide pushing forward.
ALSO KEEP in mind that the M&P 10mm 4.6 has full chamber support (which I REALLY like), but there's likely a trade-off with reliably feeding all bullet shapes.
Though in my case, my 4.6 has fired every round flawlessly except the Doubletap 200 grain hard cast rounds, which when measured have an overall length that is less that SAAMI spec.
With a full magazine of Doubletap 200 grain Hard Cast rounds, I pushed in on the opposite side of the Magazine Release to make sure it didn't move.
This time when firing, the magazine didn't fall out, and the round either was chambered, fired and brass ejected, OR it jammed with the wide front nose of the bullet jammed against the top opening of the chamber.
IN looking at the picture, I believe the magazine could also be forced out from the DOWN leverage on the magazine of the slide closing, and the rear of the cartridge being pushed down by the force of the slide pushing forward.
ALSO KEEP in mind that the M&P 10mm 4.6 has full chamber support (which I REALLY like), but there's likely a trade-off with reliably feeding all bullet shapes.
Though in my case, my 4.6 has fired every round flawlessly except the Doubletap 200 grain hard cast rounds, which when measured have an overall length that is less that SAAMI spec.
New guide rod and springs are now available for the 4.6 model from Galloway https://gallowayprecision.com/smith...-for-smith-and-wesson-m-and-p-10mm-m2-pistols
Have we figured out if any feed issues are definitively related to the guide spring or is it due to the mag springs?
I replaced my mag springs and it has been running perfectly now. See my past post with pic of old and new springs and where I bought them.
I've been dying to get into the 10mm game. But the ammo! I already have a 300blk pistol that gets next to zero attention because of the ammo cost. I know if I were to buy one of these (or a glock 40 even better) they wouldn't get the attention they deserve.
100% Correct.
Years ago I thought Indiana would be legalizing the 10MM for deer hunting and I had a Glock 20SF. After plenty of trips to the range where all I was doing was punching targets and then having to reload every round I wanted to fire it was just so much more appealing to shoot a 9mm for practice. I sold that 10mm because I didn't see the caliber being legal to hunt with on the horizon.
What got me into one now is that it's legal in Indiana and I like to go to Alaska and every time I get a little more and more farther out into the wilderness. Going through thick brush, crossing streams, and possibly wearing gloves, I liked the idea of having a thumb safety model so the M&P was the right choice for me.
Of the ammo I put a picture of up above everything ran and cycled in mine 100% reliably. There was definitely a difference in accuracy and power with all of them and the only one I would definitely not recommend is the Fort Scot ammo. I think that was keyholing or just flying completely unstable. Of the ones pictured, the Hornady Critical Duty was the winner hands down, yet I wouldn't feel comfortable shooting at a deer at 50 yards with it.
I've also worked up 100 rounds of Hornady XTP in 180gr. I just loaded up just shy of max 10mm loads with bluedot and starline brass and I wasn't really impressed with the accuracy I got. I've got some 200gr XTP's that I'm going to do the same with and hopefully have better results with.
Looking at factory ammo options, I'm amazed that when I look at the components vs factory ammo, I'm really not saving much, but I am able to make it and have it in my hands right now if needed.
Hope that helps.
I agree with teddy12B. Ft Scott ammo I used 1 day almost seemed to be hitting the target sideways. Was leaving large oval shaped hits on target. I have not really had any more feed issues since I replaced the guide rod spring with a Galloway 22lb spring and rod & I also replaced my mag springs with Springer mag springs. I listed these links in earlier feeds on this thread.
Don't get me wrong about Fort Scott as a whole, it's just that 10mm load. I actually use their 338 bullets in my handloads and I take those out to a mile in my 338 Lapua with some silly levels of accuracy and repeatability.
