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Took our 3 PCCs out for some ammo testing ... Taking the good with the bad!

IntenseImage

By IntenseImage
in Pistol Caliber Carbine

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IntenseImage Calls Shots

IntenseImage

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Spent some time yesterday afternoon getting some chrono data while locking down the PCC setups for the season.

 

We tried 2 different loads ... Both use the same powder/charge weight. The only difference is the bullet - a 124g Xtreme vs a 147g Xtreme. The 147g loads are my go-to for 3gun, Production, etc and make a 130ish PF in our handguns. The 124g loads were created simply to see if we could get the blowbacks shooting softer like the MPX. The lighter loads do feel better vs the 147s but still fall short of the softness the MPX offers. 

 

We had also thought the lighter loads would have affected dot bounce, and it does, but not by much - and while the 147s may feel a little "harder", the tracking of the dot is dead on predictable and snaps back to center VERY quickly for followup shots. 

 

PCC 1 - 16" Faxon Barrel, NERD comp, Blitzkreig buffer with delrin spacer and wave spring

PCC 2 - 14.5" QC10 barrel, Taccom, LLC long comp, Taccom 3stage buffer and wave spring

MPX - Tested with a stock 8" barrel w 4" KVP linear comp as well as a 16" barrel from In Lead We Trust with no comp

 

All strings done with 10 shots:

 

PCC 1:
124g - 971.2 fps avg, 120 fps spread, 33.43 SD ... 120.4 PF
147g - 1026 fps avg, 46 fps spread, 16.6 SD ... 150.8 PF

 

PCC 2:
124g - 929.1 fps avg, 181 fps spread, 56.93 SD ... 115.2 PF
147g - 990 fps avg, 30 fps spread, 8.46 SD ... 145.6 PF

 

MPX 8:
124g - 887.2 fps avg, 123 fps spread, 48.33 SD ... 110 PF
147g - 935.6 fps avg, 39 fps spread, 15.81 SD ... 137.5 PF

 

MPX 16:
124g - 868.8 fps avg, 131 fps spread, 51.01 SD ... 107.7 PF
147g - 949.8 fps avg, 30 fps spread, 11.37 SD ... 139.6 PF

 

I knew going in that the 147s would make PF, just didnt know what it would be - and honestly, they may be a little hotter than id like, but the guns love them and its one less thing to change when making ammo for the season. Turn the Ammobot on and let it fly - no worries on grabbing the wrong ammo when heading to a match!

 

Another interesting observation was the difference between PCC 1 and the MPX when running its 16" barrel. I guess the gas operation of the MPX is sucking up more gas than I thought, leading to considerably lower velocities/PF. 

 

The shocker was the inconsistency of the 124s. We will burn the 124s that I made up quickly for steel and will just keep running the 147g loads all season (even when PF is not a concern). What surprised me the most was the blind testing we did with our 10yr old daughter. I would hand her mags with mixed ammo and would have her slowly shoot and let me know if/when she felt a change. She noted the load change EVERY SINGLE TIME so it did confirm the feel between the 2, what I didnt expect was that she picked the 147s every time as her preferred ammo to use !

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Aircooled6racer Burned Out

Aircooled6racer

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Hello: Sounds like you need to try some 135's next. You won't get the blow back AR9's to shoot as soft as the SIG MPX. I've tried for a while to get the AR9 to shoot softer. What I found is that the AR9 shoots the best for me at 131-134PF with 124's. This is with using a timer and looking at my hits. The Sig likes it in the 138-141PF range so your 147 load is right there with the 16" barrel. I like the 115's for the Sig. Thanks, Eric

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IntenseImage Calls Shots

IntenseImage

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7 minutes ago, ChuckS said:

A couple questions: what was the powder and was there a diameter difference between the 124 and 147?

 

Thanks,

Chuck

 

 

WSF ... yes the 124s are .355 and the 147s are .357 (normally we get the .356s but they had a clearance sale on the .357 and the price was too good to pass up. Now that Ive used them, I actually prefer the .357)

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IntenseImage Calls Shots

IntenseImage

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1 hour ago, dlightning said:

What does the #2 seem to like most?  Interm of dot movement?  I have that same setup and just looking to what your data say.

 

thanks

 

 

So PCC 2 (the 14.5 QC10 barrel one) is our daughters. As noted, she picked the 147s EVERY time. She wanted to do the same blind test with her loading the mags and me telling her what I preferred and I agreed with her. While the 124s felt a TINY bit nicer, to me, the dot tracked much better with the 147s. Perhaps the higher PF worked the comp better (which btw isnt clocked straight up, we have the top ports at about 1 o'clock). When shooting and really focusing on the dot you see it move in almost a football shape -- move up to the right and snaps back down to the left. At 20 yrds or so on a 6" plate the dot would travel to the 1-2 oclock inner edge of plate and right back to center. 

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dlightning Finally read the FAQs

dlightning

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I would agree with you and your daughter.  I had the same experience.  Now I am going to try it with the weight in the bolt out and in to see the difference.  I also tried it with 115 gr and the dot movement was pretty much the same but the recoils were much sharper.  Even though the PF was at 135 vs 145 with the 124 gr coated bullets.

 

I also couldn’t get the last round to hold open with the taccom 3 stage buffer.  Hopefully after more rounds it will? 

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BartCarter Sees Sights

BartCarter

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1 minute ago, dlightning said:

...I also couldn’t get the last round to hold open with the taccom 3 stage buffer.  Hopefully after more rounds it will? 

I was told that was the design of the buffer.  It was for competition shooters that didn't care about LRBHO.  I was told to take out the plastic spacer at the end of the buffer tube.  Instead, I milled the plastic spacer until I had LRBHO.

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IntenseImage Calls Shots

IntenseImage

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None of our PCCs have a LRBHO option in either the upper or lower so it doesnt matter to me at all ... I honestly havent tried with PCC 2, but the spacer in PCC 1 is long enough that I know I cannot even manually lock the bolt back - thats how far ive limited its travel

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Shorty4087 Sees Sights

Shorty4087

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5 hours ago, Aircooled6racer said:

Hello: Sounds like you need to try some 135's next. You won't get the blow back AR9's to shoot as soft as the SIG MPX. I've tried for a while to get the AR9 to shoot softer. What I found is that the AR9 shoots the best for me at 131-134PF with 124's. This is with using a timer and looking at my hits. The Sig likes it in the 138-141PF range so your 147 load is right there with the 16" barrel. I like the 115's for the Sig. Thanks, Eric

My results matched Eric’s and accuracy was slightly better with the 124’s allbthe way out to 75 yds. The 147’s were close in accuracy, but I felt that the 124’s were softer (as you would suspect) than the 147’s . I also felt that the bolt cycled faster as well. These results were with TG out of a CMMG Mk9 with TACCOM 3-stage buffer. Playing with a slower burning powder now to take full advantage of the 16” barrel this week and will share with the group...

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MikieM Calls Shots

MikieM

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8 minutes ago, STI gunner said:

Mikie, i'm using 3.3  N320 at 1.120  with 124 RN and 130 PF out a 16" barrel also, very nice load !!

 

Yep. My OAL is the same. 

I'll check it again down the road on a warm day and if I have to I'll add a tenth more grain of powder.

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