This is a range report of the PWS MK112 300BLK (in a pistol set up), using both subsonic and supersonic factory rounds, suppressed and unsuppressed. I hope the info helps someone looking into the PWS line.
My main conclusions:
This rifle does best with shooting suppressed supersonic rounds, and also performs nearly as well with unsuppressed supersonic;
The rifle has big problems with unsuppressed subsonic rounds (all but one brand failed to cycle);
It performs well with suppressed subsonic rounds, but I had to deviate from the factory-recommended gas block setting.
My setup is a PWS MK 112 upper, placed on a MK 109 lower. Suppressor is YHM Phantom Ti 30 cal.
Be aware, this model has an adjustable gas block , with settings ranging from "1-circle" down to "4-circle," as illustrated on the following link:
http://primaryweapons.com/firearms/mk1/piston/#.VWXmu2fbKi4
The factory recommends using the 1-circle setting when shooting standard rounds unsuppressed. They recommend using the 3- circle setting when using standard rounds suppressed.
I will indicate the gas block setting, when it is pertinent. In some instances, I had to deviate from the factory recommendation, before a given round would successfully cycle. If a round failed to cycle in the 1-circle setting, I assumed it would also fail in the other settings.
The factory rounds tested are as follows (I indicate the muzzle velocity stated on box, when provided ):
SUBSONIC:
Jamison 208 gr. A-Max Prowler Grade (1040 fps)
Gemtech 187 gr. (black tip) "cosmetic blemish" version
Remington UMC 220 gr. OTFB
Remington 220 gr. OTM
Underwood 220 gr HPBT (1030 fps)
SUPERSONIC:
Cor-Bon 125 gr. BTHP green tip (2250 fps)
Remington Premier Match 125 gr. OTM
Underwood 110 gr. V-MAX (2250 fps)
Hornady Custom "300 Whisper/BLK" 110 gr. V-MAX (2350 fps)
Barnes VOR-TX 110 gr. TAC-TX (2350 fps)
CONCLUSIONS:
Subsonic unsuppressed:
Using the 1-circle setting in all cases...
The ONLY round that cycled successfully was the Remington UMC 220 grain OTFB.
However, there was a fail to hold open after the last round.
Subsonic suppressed:
Underwood 220 HPBT works normally on the 1-circle setting (3-circle setting failed, 2-circle setting not tested).
Remington UMC 220 grain OTFB works normally on the 1- circle and 2- circle settings (3- circle setting worked except no hold open after the last round).
Remington High-performance Rifle 220 grain OTM works normally only with the 1- circle setting (the 2- and 3- circle settings failed).
Gemtech 187 gr Cosmetic Blemish cycled normally on the 1-circle setting, however, there was no hold open the last round.
The Jamison failed to cycle at the 1-circle setting.
Supersonic unsuppressed:
All the rounds (EXCEPT the Cor-Bon) cycled fully normally, with normal hold open. The Cor-Bon rounds ejected, but had FTF subsequent rounds. All testing was with the 1- circle setting.
Supersonic suppressed:
All five factory rounds tested fully normal, with normal cycling and normal hold open (3-circle setting).
(My next post will be a similar report on the PWS MK 109 300 BLK.)
My main conclusions:
This rifle does best with shooting suppressed supersonic rounds, and also performs nearly as well with unsuppressed supersonic;
The rifle has big problems with unsuppressed subsonic rounds (all but one brand failed to cycle);
It performs well with suppressed subsonic rounds, but I had to deviate from the factory-recommended gas block setting.
My setup is a PWS MK 112 upper, placed on a MK 109 lower. Suppressor is YHM Phantom Ti 30 cal.
Be aware, this model has an adjustable gas block , with settings ranging from "1-circle" down to "4-circle," as illustrated on the following link:
http://primaryweapons.com/firearms/mk1/piston/#.VWXmu2fbKi4
The factory recommends using the 1-circle setting when shooting standard rounds unsuppressed. They recommend using the 3- circle setting when using standard rounds suppressed.
I will indicate the gas block setting, when it is pertinent. In some instances, I had to deviate from the factory recommendation, before a given round would successfully cycle. If a round failed to cycle in the 1-circle setting, I assumed it would also fail in the other settings.
The factory rounds tested are as follows (I indicate the muzzle velocity stated on box, when provided ):
SUBSONIC:
Jamison 208 gr. A-Max Prowler Grade (1040 fps)
Gemtech 187 gr. (black tip) "cosmetic blemish" version
Remington UMC 220 gr. OTFB
Remington 220 gr. OTM
Underwood 220 gr HPBT (1030 fps)
SUPERSONIC:
Cor-Bon 125 gr. BTHP green tip (2250 fps)
Remington Premier Match 125 gr. OTM
Underwood 110 gr. V-MAX (2250 fps)
Hornady Custom "300 Whisper/BLK" 110 gr. V-MAX (2350 fps)
Barnes VOR-TX 110 gr. TAC-TX (2350 fps)
CONCLUSIONS:
Subsonic unsuppressed:
Using the 1-circle setting in all cases...
The ONLY round that cycled successfully was the Remington UMC 220 grain OTFB.
However, there was a fail to hold open after the last round.
Subsonic suppressed:
Underwood 220 HPBT works normally on the 1-circle setting (3-circle setting failed, 2-circle setting not tested).
Remington UMC 220 grain OTFB works normally on the 1- circle and 2- circle settings (3- circle setting worked except no hold open after the last round).
Remington High-performance Rifle 220 grain OTM works normally only with the 1- circle setting (the 2- and 3- circle settings failed).
Gemtech 187 gr Cosmetic Blemish cycled normally on the 1-circle setting, however, there was no hold open the last round.
The Jamison failed to cycle at the 1-circle setting.
Supersonic unsuppressed:
All the rounds (EXCEPT the Cor-Bon) cycled fully normally, with normal hold open. The Cor-Bon rounds ejected, but had FTF subsequent rounds. All testing was with the 1- circle setting.
Supersonic suppressed:
All five factory rounds tested fully normal, with normal cycling and normal hold open (3-circle setting).
(My next post will be a similar report on the PWS MK 109 300 BLK.)
