Sig MPX carbine 124 gr. Load data

[magoo]

I'm looking for some load data for 124 gr. Bayou Bullets, or any loads for the Sig MPX carbine. 

[shutr]

Just got my MPX carbine and only had one opportunity to get to the range and sight it in. It would not run reliably with my 130PF loads, one out of every 5 would not eject or would short cycle the bolt. I think they need a break in period. I also tried a load of 4.0gr Tightgroup with a 124gr JHP, much better! Cases eject about 6-8 ft., accuracy at 25 yds was acceptable. Since the range I was at will not let you shoot fast, I don't know how the load will work under match conditions. That test will be at a different range. My MPX also likes lots of lube, runs smoother. 

[CZ85Combat]

Run about 500 rounds of factory ammo and then try some fast powder... N310, Nitro 100, E3, Ramshot Competition, Clays, 700X

In the Gen II's Sig made the gas port smaller so it may not rum well with 126pf-130pf reloads.

The 16" barrel will give you about 100 fps faster then a pistol.

I am using 147(150) Blue Bullets with 2.4 gn N310 @ 1.150 OAL  860 fps = 129 pf

125 Blue Bullets  with 2.8 N320  @ 1.110 OAl  1027 fps = 128 pf

[magoo]

I have some N320 think i'll try it with some 124 gr.  My production load of 4.0 gr. of N320 was not reliable. Gun has only ran about 200 rounds. Think I'll go to 4.2 of N320 with 124 gr. Bayou bullets and see if that works.

[CZ85Combat]

I don't know what OAL you are using, have you done the push test?     4.2gn of N320 is a max load.  out of a 16" barrel you are going to be 155 + pf.  If it did not run with the 4.0 of N320 it probably will not run with the 4.2.   You need to shoot 500 rounds of factory ammo before you use your reloads!

Edited September 12, 2016 by CZ85Combat

[magoo]

Done the push test. I'm running  3.9 gr. N320 , 1.140 OAL,  124 gr. bayou bullets =130 PF,  In a cz spo1 shadow. My mistake 3.9 not 4.0. I'll run the factory ammo like you said. then give the N320 a try.

Thanks 

[CZ85Combat]

If you are going to be using your MPX in PPC you don't want to use your CZ SP01 loads.  You want to load to 130pf in your MPX, your CZ load is going to be 145pf-155pf in your MPX. it will shoot a lot softer with loads that run 130pf in it.  You will need a faster powder then N320  to load low enough.   2.5gn of  N310  with a 147gn bullet  132pf  is so soft with a 16" barrel, as long as your MPX will run with it.

[magoo]

Took the MPX out to the range. Used some hand loads that are 4.8 grs. N340, 124 gr. Bayou TCG, 1.140 OAL, 1249 FPS, Gun was reliable and very accurate.