GregJ

Just got the BCG and fp upgrade from Sig my my Gen2 MPX. Ran a few rounds through. Though some of the primers looked cratered. Left is Accurate #2, 4.2gr, Zero 124 @ 1.125. CCI Primer. Center is E3 3.6gr, Zero 124 @1.100. Win SP primer. Chronos 1080/pf 134 Right is 115gr Remington ammo. The E3 is my main minor load and shoots well out of my 1911. Thoughts?

I've been running a SSA in my MPX, but wondering if I should go back to stock now that Geissele is stating their triggers are not compatible with the MPX. Sometime this year they are supposed to come out with a SSA-MPX. https://geissele.com/super-3-gun-s3g-trigger.html

If anyone is interested, here is a pic of the original BCG and the upgrade Sig sent. The new FP is a tad shorter. The original was 2.76 and the new us 2.65 - IIRC. I will see how it works tomorrow.

I had a nice set I bought from Grainger years ago. They finally were starting to get flaky, needing to be rest too often. I picked up a digital caliper from Home Depot, their Husky brand. Price was very reasonable, and so far they have worked quite well.

This week I was getting pierced primers with Freedom Munitions (I know) 115gr RN New, when I chrono'd them. I ran this in my 1911 SS with no issues. Last sat, my reloads had bulged brass, they were pulls that I reloaded and was burning up, 115 and 124gr, 3.6gr E3, 1.100/.3775. I know the 124s with 3.6 chrono'd at about 1080, and the Freedom chrono'd about 1180. Neither were "hot" loads. I know the barrel was leaded up pretty bad. This may have caused increase pressure, causing both issues. Will know for sure when I get the new BCG and start testing.

Good idea, will look tonight. The vent port looked awfully clean, so I dont think any gas has been vented in a long time, if ever (I bought it used, supposed low round count). Thanks

Thanks for the info. I dont have a cycling issue, mine is pierced primers and bulging cases. Sig is sending me a new BCG, hopefully that will fix the issue. I took advantage of the down time for it to break it down and give it a good cleaning. This is when I found things all gunked up, so bad no gas could have made it through the valve. If you take a punch are you able to push the bleed valve any at all? Just want to make sure mine is not locked up internally. I may take it apart tonight to verify.

I've not done a side-side comparison, but I have been very happy with my AmmoBot, and especially the customer service. I like having the handle available so I can easily clear jams, or run a few loads through manually if working up a load, etc.

Anyone taken theirs apart? I decided to pull the barrel and clean mine and it was severely carboned up. The hole on the gas side of the valve was so clogged up I had to take a pick to clean it out. The gas ring appears to be so loaded with carbon it will not move. I am soaking it in Kroil overnight and will see what they look like tomorrow aft. I assume the valve is supposed to move but it appears to be frozen. Just wonder if I should take it apart to clean it. I picked it up used with a supposed low round count. I know the manual says to service it every 5k rounds. I have put over 3k through it myself and am surprised how carboned up it was.

A knowledgable friend suggested the bulges were due to firing out of battery. I will call Sig this am and see what they say about this and the firing pin. EDIT: Called Sig CS, they are sending an upgraded BCG which includes FP and FP spring. Seems they dropped the FP spring with the Gen2, and are adding it back. Interesting. He didnt have much input on the case bulge, other than stay away from Freedom ammo. Of course he also suggested to stay with factory ammo. We'll see how the upgraded BCG helps with the bulging.

And the hits just keep coming. Appears The Freedom ammo I chrono'd this aft has pierced primers. Looked at the firing pin. Dont have a new one to compare too, but will order a couple.

I understand that. I guess I was under the impression the MPX did not have this issue. Partly because I just now noticed it, after putting about 3k rounds thru it. But it indeed has an unsupported chamber. So I guess some bulging is normal with this gun.

I chrono'ed a few rounds this evening, and believe either some of the reloads in question were a little long (hitting the lands causing a pressure spike), or loaded heavy. String below is 6 rounds of Freedom Munitions New 115gr RN. (Avg and PF calculated by my CED). Shot these for comparison purposes. 1206 1212 1249 1178 1216 1228 Avg= 1214 PF= 139.7 NOTE: There were very slight marks from the unsupported area of the chamber on a couple pieces of brass. You would miss it if you were not looking for it. The CCI primers did have a black dot from the firing pin. looked like a hole but wasnt - very strange. String below is 6 rounds 124gr Zero, 1.100/.3775, 3.6gr E3 (Avg and PF calculated by my CED) 1060 1065 1095 1090 1078 1097 Avg=1080 PF=134.0 NOTE: 2 pieces had a slightly more visible impression from the unsupported area of the chamber, but no "bulge". Rest looked fine. Looks like 3.4-3.5gr of E3 might be the sweet spot as far as PF goes. Or maybe load a little shorter. More testing/chrono work, but I think I have the answers now.

Absolutely possible. Still need to check this just havent gotten to it, though I was loading the rounds in question at 1.100/.3775. tks

I am beginning to think the E3 is just too fast for the MPX. This would explain the bulge. I will try chronoing a few rounds and see.

I was planning on doing that this weekend, as well as some of my regular loads. tks

LOL Nope. To clarify, I was burning up rounds that had been pulled apart, as they were loaded when I first got my 1050 and was trying to get it sorted out. All swagged/over crimmped bullets were culled out, as was anything else that had an issue, The rounds were loaded with 3.6gr of E3, which shoots well out of my 5" 1911 SS, about 131PF. Thinking about it more, some of the rounds felt light - not sure why. Also some of the pulls were 115s plated, most were 124gr jacketed. I did have one that the case let loose at the bulge, which was interesting.

I've put nearly 3k rounds through it and first time I have seen this. Definately from the chamber.

Burned up some light reload rejects this weekend in my Sig MPX Carbine and noticed a lot of bulged brass, very similar to the infamous Glock bulge. First I had noticed this. I think because the loads were light. Anyone run into this?

I broke punches too. Finally found a small enough nail set punch znd that worked. Definately goes out one way. One side of arm seems to be machined tighter. Look at the video on FFB web site for which way.

I've got 16# to burn up. I really like it, and may just keep using it instead of WST or W231. One advantage I found out, the flakes are too big to make it through the flash hole. This is handy if you miss a primer, you dont get powder everywhere. I will post some data tonight.

Thanks. I've messed with the Hornady dies/rings for years, they always tick me off cause the flats are always in the wrong spot. Not a prob now. ?

I like RCBS die locks and put them on my Forrester dies. They are 1-3/16 , so I ordered a Tekton wrench from Home Depot. $20 delivered to my store. Cut it in half, dipped the end in plasti-dip. And the box end fits perfectly between the dies.

That is awesome. I was afraid of getting one because of all the issues I was reading about. Hope it continues to work 100% for you.

Yes, sorta, though I have to admit I didnt do a feature/feature comparison. A local dealer <<== LINKY sells the 1050 with AB all set in the caliber you want, and can take 3 months to pay. This was a big deal to me, as I knew it would be easier to get the CFO to approve 3 relatively reasonable chunks instead of one BIG chunk. And so far the AB has worked quite well, and the support has been fantastic. Plus it retains the handle so it is easier to clear jams, or load individual rounds if needed. I am coming from a LNL with case and bullet feeder. I am starting to shoot a lot of 9mm, and wanted the ability to handle crimped primers, so the 1050 was a natural choice. Each are very good in what they do. It just depends on which one fits your needs the best, then that one is "the best".