Anyone use a Glock 19 ISMI spring in their M&P9 FS?

[PC Geek Shooter]

I have a new M&P9 FS 4.25" and I got ISMI #: 11, 13 and 15 recoil springs from SSS. I have a Dillon 650 (well uncle and I together) and have been making notes with Titegroup and seeing how low I can go. With the very low ones I am shooting one at a time and making sure I see a hole, just in case of a squib. At this time I don't feel comfortable going below 2.1 GN of TiteGroup, even though I feel safer using that RCBS Lock-Out Die, this is the lowest I see myself going with TG.

I also purchased a Wolff spring (MidwayUSA 153024) for my uncle's S&W 6904 (3.25" or so), but got him the 10# one for the same type model (5904) but it was a little longer (I'll have to cut off a few of the wires). I probably should of gotten a 13# or 14# one to cut to make it more like a true 9# or 10#, since this 10# might turn out to be a 6.5 to 7# when I'm done putting it in his. With this Wolff 10# 4.0" one I got down to 2.1 GN with TiteGroup, I could only go down to 2.7-2.8 GN with the ISMI 11# one for the best reliability, ie. no FTE.

So I called up ISMI today and spoke to the owner (nice guy) and asked some questions on their springs. I've been reading here that some people say that the ISMI ones are usually 1.5 to sometimes 2.0 lbs less than similar Wolff ones. Turns out that his springs are a little bit different and he tries to keep it locked up a little longer than say a Wolff spring (which didn't know about before). Which, is really good for the M&P9 FS and 5" models for sure. I know I heard something about P1 and ..... but he explained it good and I got the gist of it.

I didn't want to buy Wolff #; 9, 10 springs (made for another model, not the M&P) that were 4.25" and would basically be exactly like the ISMI 11# ones, so I could save time and money not screwing around, well at least keep it to a minimum.

So I got around to my main question after I learned that his springs keep the gun in lockup longer, then I knew I wanted to try some of his springs from __another model__ that could work in my M&P9 FS. It turns out that he recommended the G19 15# and I told him I might as well try the 13# as well. He said he was going to be shipping to SSS on Tues so I msg'd SSS and they called back and said they would hopefully get a msg to ISMI in time for them to put in a G19 #: 13 and 15 spring. Granted in my msg I also gave them my invoice number from a few weeks ago so that obviously helped in them knowing that I was serious, since SSS does not have these springs on their website.

So I'm hoping this will be the ticket for me. The net effect hopefully will allow me to shoot TiteGroup from 2.1 to 2.3 GN and I'd be very happy. Why??? Because I can. My neck and upper body hurt constantly, so since I have a reloading machine, I might as well use it to do things that will make shooting more fun (less painful).

I was just going to get a Wolff 4.5" to 5" model (probably 9mm) and cut the wires, I assumed I'd have to get a higher lb spring, but also didn't want to have to buy 5-10 springs to make it work (still may have to buy a couple others, but I'm on the right path). Also a bonus that the ISMI ones fit the stock guide rod, even though I bought the SSS steel one so I could easily switch out. I might just buy a few factory ones once I figure out 2-3 of my favorite loads, screw the aftermarket springs into the stock guide rod. That way I'll have a mouse fart load, maybe a bunny fart one and then one that I could use the ISMI M&P FS 13# spring while doing minor PF with IDPA and/or USPSA.

I've also got the Wolff reduced striker spring and that worked on all the 2.1 GN to 2.8 GN ones I shot last time with Federal primers so I'm happy with that. I also lightly polished the trigger bar. Put in the Apex Competition big sear plunger to take down the weight just a little bit. I then really filed down and polished up the factory sear and firing pin block (Apex calls USB) to what the pdf by Dan Burwell on M&P trigger jobs said. So my sear and firing pin block look very, very similar to the Apex parts, it's a vast improvement. Now I can't wait for that Apex AEK polymer trigger to come out, I have a hard time justifying $75 just for an aluminum trigger. Of course on my previous M&P9L I had the FSS & Trigger, which was beyond great, but this time I wanted to save some money and do some of it myself.

[Matt1911]

Holy long post Batman.