Sig MPX?

[HeavyDuty]

The problem with buying the MPX-K is that the (rather substantial) cost is just the first step. Adding BUIS and a RDS is almost another $800. Yikes.

I’m really happy with the arrangement I have on my Scorpion-K and Rattler - MBUS Pros with a Romeo4T on a Reptilia lower 1/3 mount - so I’m doing that again. I just need to wait for another sale on the Romeo4T, current pricing is back up there. I did get the BUIS and mount ordered, Reptilia availability can be sketchy.

Toss in a few more magazines, and we’re very quickly looking at a $3k pistol. And then there”s the cost of SBRing…

[HeavyDuty]

I thoroughly enjoy mine. Much less concussion and recoil than my Rattler.

Attachment 82055

I saw your comments upthread about the stock. Are you still happy with it? I’m planning on SBRing my MPX-K, and the telescoping stock has a lot of appeal - I’ve handled but not shot them. I doubt I’d ever have to deploy in a restricted space like a car, but I tried it out of curiosity - unfolding the stock on my Scorpion and the brace on my Rattler in the car is like trying to refold a map in a phone booth.

[Odin Bravo One]

[JCN]

175 on the match upper no problem even with magazine #3.



Practice gun: 10650 of Syntech 150
Rounds since cleaned: gas 650, bolt 650
Parts broken: 0

Items replaced due to wear:
Tappet gas ring 5500 rounds, $2.50 replacement.
Extractor spring and donut at 5750 rounds ~$5.00
Tappet #2 gas ring 5000 rounds
Gas plug #1, 2 gas rings 5000 rounds ~$12
Firing pin and spring 10000 rounds ~$42
Hammer pins and springs 10000 rounds ~$12
Extractor spring and donut at 10000 rounds


Malfunctions after the initial tuning: 5
1. Second to last round jam in new 20 round plus extension, subsequently no issues.
2. Trigger didn’t reset once during a session, DUE TO MY ERROR INSTALLING hammer spring legs under the pin and the pin walked.
3. FTE replaced the extractor spring and donut at 5750
4. FTE at 2600 on gas system without cleaning and 2500 on extractor spring
5. FTL at 10000 rounds early in practice mag 2. Will try and tune mag.



———-
Match upper: 2225
Rounds since cleaned: 275

Malfunctions: initial tuning phase
1. Single FTL (match upper) with 20 round mag in 30 degree weather with full magazine attributable to a caulked charging handle not allowing bolt closure. Resolved with stock charging handle and tested in cold.
2. Had another FTL with the match upper with a new 30 round mag and extension that I had not ever used before. I had a FTL about 5 rounds in.
3. FTL with Syntech and FTE with Lawman. Same magazine as #2. Changed recoil springs to known red -25% strength, changed extractor spring and post, changed magazine spring and follower. With no malfunctions after.
4. FTL with Syntech, same magazine. 1250 rounds since cleaning. Clean and polish feed lips and magazine. Polished feed ramp of barrel.

Rounds since last malfunction: 275

[JCN]

Testing a new compensator and clocking to 1 o’clock position.

Also tested 150 Syntech against the Eley and I swear I like the Syntech better.






Practice gun: 10650 of Syntech 150
Rounds since cleaned: gas 650, bolt 650
Parts broken: 0

Items replaced due to wear:
Tappet gas ring 5500 rounds, $2.50 replacement.
Extractor spring and donut at 5750 rounds ~$5.00
Tappet #2 gas ring 5000 rounds
Gas plug #1, 2 gas rings 5000 rounds ~$12
Firing pin and spring 10000 rounds ~$42
Hammer pins and springs 10000 rounds ~$12
Extractor spring and donut at 10000 rounds


Malfunctions after the initial tuning: 5
1. Second to last round jam in new 20 round plus extension, subsequently no issues.
2. Trigger didn’t reset once during a session, DUE TO MY ERROR INSTALLING hammer spring legs under the pin and the pin walked.
3. FTE replaced the extractor spring and donut at 5750
4. FTE at 2600 on gas system without cleaning and 2500 on extractor spring
5. FTL at 10000 rounds early in practice mag 2. Will try and tune mag.



———-
Match upper: 2400
Rounds since cleaned: 450

Malfunctions: initial tuning phase
1. Single FTL (match upper) with 20 round mag in 30 degree weather with full magazine attributable to a caulked charging handle not allowing bolt closure. Resolved with stock charging handle and tested in cold.
2. Had another FTL with the match upper with a new 30 round mag and extension that I had not ever used before. I had a FTL about 5 rounds in.
3. FTL with Syntech and FTE with Lawman. Same magazine as #2. Changed recoil springs to known red -25% strength, changed extractor spring and post, changed magazine spring and follower. With no malfunctions after.
4. FTL with Syntech, same magazine. 1250 rounds since cleaning. Clean and polish feed lips and magazine. Polished feed ramp of barrel.

Rounds since last malfunction: 450

[JCN]

Practice gun: 10800 of Syntech 150
Rounds since cleaned: gas 800, bolt 800
Parts broken: 0

Items replaced due to wear:
Tappet gas ring 5500 rounds, $2.50 replacement.
Extractor spring and donut at 5750 rounds ~$5.00
Tappet #2 gas ring 5000 rounds
Gas plug #1, 2 gas rings 5000 rounds ~$12
Firing pin and spring 10000 rounds ~$42
Hammer pins and springs 10000 rounds ~$12
Extractor spring and donut at 10000 rounds


Malfunctions after the initial tuning: 5
1. Second to last round jam in new 20 round plus extension, subsequently no issues.
2. Trigger didn’t reset once during a session, DUE TO MY ERROR INSTALLING hammer spring legs under the pin and the pin walked.
3. FTE replaced the extractor spring and donut at 5750
4. FTE at 2600 on gas system without cleaning and 2500 on extractor spring
5. FTL at 10000 rounds early in practice mag 2. Will try and tune mag.



———-
Match upper: 2400
Rounds since cleaned: 450

Malfunctions: initial tuning phase
1. Single FTL (match upper) with 20 round mag in 30 degree weather with full magazine attributable to a caulked charging handle not allowing bolt closure. Resolved with stock charging handle and tested in cold.
2. Had another FTL with the match upper with a new 30 round mag and extension that I had not ever used before. I had a FTL about 5 rounds in.
3. FTL with Syntech and FTE with Lawman. Same magazine as #2. Changed recoil springs to known red -25% strength, changed extractor spring and post, changed magazine spring and follower. With no malfunctions after.
4. FTL with Syntech, same magazine. 1250 rounds since cleaning. Clean and polish feed lips and magazine. Polished feed ramp of barrel.

Rounds since last malfunction: 450

[HeavyDuty]

I saw your comments upthread about the stock. Are you still happy with it? I’m planning on SBRing my MPX-K, and the telescoping stock has a lot of appeal - I’ve handled but not shot them. I doubt I’d ever have to deploy in a restricted space like a car, but I tried it out of curiosity - unfolding the stock on my Scorpion and the brace on my Rattler in the car is like trying to refold a map in a phone booth.

I should have tagged you - @Sensei .

[JCN]

Practice gun: 10800 of Syntech 150
Rounds since cleaned: gas 800, bolt 800
Parts broken: 0

Items replaced due to wear:
Tappet gas ring 5500 rounds, $2.50 replacement.
Extractor spring and donut at 5750 rounds ~$5.00
Tappet #2 gas ring 5000 rounds
Gas plug #1, 2 gas rings 5000 rounds ~$12
Firing pin and spring 10000 rounds ~$42
Hammer pins and springs 10000 rounds ~$12
Extractor spring and donut at 10000 rounds


Malfunctions after the initial tuning: 5
1. Second to last round jam in new 20 round plus extension, subsequently no issues.
2. Trigger didn’t reset once during a session, DUE TO MY ERROR INSTALLING hammer spring legs under the pin and the pin walked.
3. FTE replaced the extractor spring and donut at 5750
4. FTE at 2600 on gas system without cleaning and 2500 on extractor spring
5. FTL at 10000 rounds early in practice mag 2. Will try and tune mag.



———-
Match upper: 2500
Rounds since cleaned: 550

Malfunctions: initial tuning phase
1. Single FTL (match upper) with 20 round mag in 30 degree weather with full magazine attributable to a caulked charging handle not allowing bolt closure. Resolved with stock charging handle and tested in cold.
2. Had another FTL with the match upper with a new 30 round mag and extension that I had not ever used before. I had a FTL about 5 rounds in.
3. FTL with Syntech and FTE with Lawman. Same magazine as #2. Changed recoil springs to known red -25% strength, changed extractor spring and post, changed magazine spring and follower. With no malfunctions after.
4. FTL with Syntech, same magazine. 1250 rounds since cleaning. Clean and polish feed lips and magazine. Polished feed ramp of barrel.

Rounds since last malfunction: 550

[JCN]

That fucking magazine #3 and FTLs. I’m wondering if the extension doesn’t have a burr or issue.
I may also try using drops of oil in the chamber when it’s dry like ~500 rounds or so.






Practice gun: 10800 of Syntech 150
Rounds since cleaned: gas 800, bolt 800
Parts broken: 0

Items replaced due to wear:
Tappet gas ring 5500 rounds, $2.50 replacement.
Extractor spring and donut at 5750 rounds ~$5.00
Tappet #2 gas ring 5000 rounds
Gas plug #1, 2 gas rings 5000 rounds ~$12
Firing pin and spring 10000 rounds ~$42
Hammer pins and springs 10000 rounds ~$12
Extractor spring and donut at 10000 rounds


Malfunctions after the initial tuning: 5
1. Second to last round jam in new 20 round plus extension, subsequently no issues.
2. Trigger didn’t reset once during a session, DUE TO MY ERROR INSTALLING hammer spring legs under the pin and the pin walked.
3. FTE replaced the extractor spring and donut at 5750
4. FTE at 2600 on gas system without cleaning and 2500 on extractor spring
5. FTL at 10000 rounds early in practice mag 2. Will try and tune mag.



———-
Match upper: 2700
Rounds since cleaned: 750

Malfunctions: initial tuning phase
1. Single FTL (match upper) with 20 round mag in 30 degree weather with full magazine attributable to a caulked charging handle not allowing bolt closure. Resolved with stock charging handle and tested in cold.
2. Had another FTL with the match upper with a new 30 round mag and extension that I had not ever used before. I had a FTL about 5 rounds in.
3. FTL with Syntech and FTE with Lawman. Same magazine as #2. Changed recoil springs to known red -25% strength, changed extractor spring and post, changed magazine spring and follower. With no malfunctions after.
4. FTL with Syntech, same magazine. 1250 rounds since cleaning. Clean and polish feed lips and magazine. Polished feed ramp of barrel.
5. FTL with Syntech, still that same magazine #3 early into the mag. Am going to swap the spring from my practice mag into the #3 body.

Rounds since last malfunction: 0

[JCN]

Comparing the amount of drag in the BCG in the upper, there’s a lot less drag in the practice upper…

Going to add the following pre-match routine to aid during break in:

1. Bore snake the barrel.
2. Remove and wipe down the BCG
3. Oil the BCG.