9mm PCC Accuracy at 50 yds

[Greg5611]

Thought I had a good couple of loads for my new 9mm PCC ( 3.9 gr VV n320 using 124 gr Berry’s coated bullets COL 1.150; 4.0 gr TiteGroup with 124 gr Berry’s coated bullets) 1.5” to 2.0” groups at 25 yds and minimal recoil/dot movement.  However, when sighting in these same loads at 50 yds, hits were all over the map, no group consistency whatsoever.  What do I need to do to get a decent group size at 50 yds?  I currently don’t sort my brass or do anything special as far as brass prep goes.  Maybe I’m crimping plated bullets too light or too tight?  Most of my USPSA shooting is <15 yds so this has never been an issue until I tried to push beyond 25 yds.  Factory rounds will give me 2+” groups so I know it’s something I’m doing/not doing in the reloading process.  Help,please?

[MemphisMechanic]

Try bullets that arent plated. They’re rather notorious for mediocre accuray. Go load a batch of FMJ or coated and see what happens.

 

That said, pull a bullet and check for over-crimping before you write them off...

 

You crimp die should be considered a flare removal die, and remove all belling from the case. And no more than that.

 

Pull a bullet. If there is more than a very faint line where the case mouth was resting on the bullet, you are crimping them too much and likely swaging the bullet down to a smaller diameter. You should not be able to feel the ridge in the side of the bullet with your fingernail.

 

(Note: digital calipers are usually accurate to +/- .001” and not accurate enough to check for this. Do it by feel.)

 

Edited November 22, 2017 by MemphisMechanic

[Ofishl1]

Agreed..myself and another Master level shooter had the problem with Montana Golds in 124 CMJs ..all over the range by feet..not inches...tried a very light crimp..didnt help...now I run Berrys TP and Frontier 121s TC and they do well out to 150 yards ..straight with normal drop running viht 320 at 4.3 with a .001 -.002 crimp

[jkrispies]

What exactly was your group size at 50 yards, and what do you want?  Start with your end in mind... and remember that USPSA isn't bullseye.  How often are you actually shooting to 50 yards?

 

MemphisMechanic offered some sage advice.  I'm load developing my PCC right now as well, and I was able to hit a 10" plate offhand at 65 yards with 100% accuracy... excepting the shots that I called as misses, and sure enough even those times the bullet went where I told it to go.  I don't personally care to shoot groups, but I was hitting what I needed to hit in the center of the plate-ish, so I left the range happy.  This was with moly-coated lead 135's.  I tweaked my OAL a bit when I got home which will help, but I'm not sweating it past that as long as my velocity settles down some more.  If I really wanted to go better than what I shot today, I'd invest in FMJ's but I frankly don't see a need for the added expense.

[jkrispies]

One other thought based on my current testing...

 

Try shortening your OAL.  I started out at 1.150" as well and thought I was good until I attempted to eject an unfired round and the bullet stuck in the lands.  I believe this is due to inconsistent length and/or ogive on the bullets themselves so that a random few were ending up with a significantly longer OAL than others, thus planting a handful in the lands and causing the pressure/velocity to spike slightly.  This isn't something that would show in the case gauge, by the way.  I first had this clue due to some random velocity spikes that I couldn't otherwise explain, about one out of every 20 rounds.  I just adjusted my OAL down to 1.130" and measured the OALs of about 20 and sure enough a few of them crept up to 1.140" and some change, which verifies my theory and should now keep the random long-sters out of the lands.  I'm pretty sure my velocities will settle now.  If this same thing is happening with your rounds, it's something that you probably wouldn't see in your groups measured at 25 yards but it would be more apparent at 50 yards.

Edited November 22, 2017 by jkrispies

[Flatland Shooter]

2 hours ago, Ofishl1 said:

 

I run Berrys TP and Frontier 121s TC and they do well out to 150 yards ..straight with normal drop running viht 320 at 4.3 with a .001 -.002 crimp

 

 

What weight Berrys bullets are you using?  The 124  grain target hollow point?

 

Also, where are you able to purchase the Frontier 121 TC bullets?  Black Hills will only sell them to FFL holders.

 

Thanks.

[1911luvr]

One other thought based on my current testing...
 
Try shortening your OAL.  I started out at 1.150" as well and thought I was good until I attempted to eject an unfired round and the bullet stuck in the lands.  I believe this is due to inconsistent length and/or ogive on the bullets themselves so that a random few were ending up with a significantly longer OAL than others, thus planting a handful in the lands and causing the pressure/velocity to spike slightly.  This isn't something that would show in the case gauge, by the way. 

1.15 is well beyond what most PCC barrels can handle if they haven't been reamed. JP and Wilson Arms are the two barrels I know that can handle that length without sticking in the leade. Remind me and I can bring my reamer to the next match.


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[jkrispies]

6 hours ago, 1911luvr said:

 

1.15 is well beyond what most PCC barrels can handle if they haven't been reamed. JP and Wilson Arms are the two barrels I know that can handle that length without sticking in the leade. Remind me and I can bring my reamer to the next match.


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Thanks for the offer but no need to ream. I ran about 20 through my chamber at the new length last night and they all extracted without marks in the moly. I’m going camping in the dessert for thanksgiving and bringing my chrono and 100 rounds with. Will sneak off and do velocity testing at some point.  

Edited November 22, 2017 by jkrispies

[Ofishl1]

I ran a KAW barrel that would only run loads under 1.100, then went to a WIlson barrel and it will eat most profiles out to 1.120, however..MG 124 JHP and any TC's like Berrys , or other JHP's like Deltas I still have to load max at 1.080 then there are no feeding issues. I went  thru all my favorites profiles and did a drop test until I found the happy OAL and backed them off ..010 to compensate for varying brass lengths, some brass I measured were .005 to .008 variance.

My max is the same as a factory white box 124g round nose are 1.110 on average, this tells me to stay away from loading long even if you can.

[jkrispies]

9 hours ago, Ofishl1 said:

I ran a KAW barrel that would only run loads under 1.100, then went to a WIlson barrel and it will eat most profiles out to 1.120, however..MG 124 JHP and any TC's like Berrys , or other JHP's like Deltas I still have to load max at 1.080 then there are no feeding issues. I went  thru all my favorites profiles and did a drop test until I found the happy OAL and backed them off ..010 to compensate for varying brass lengths, some brass I measured were .005 to .008 variance.

My max is the same as a factory white box 124g round nose are 1.110 on average, this tells me to stay away from loading long even if you can.

Hmmm....   I don’t doubt this is true, but why would PCC barrels/chambers in particular be manufactured in a manner that is different from the accepted standard?  Lots of loading manuals list OAL as 1.145 - 1.150 for various loads. What’s the benefit to the manufacturers to deviate from the norm, especially if it has the potential to limit the usability of their product?  

[MemphisMechanic]

15 hours ago, jkrispies said:

Thanks for the offer but no need to ream. I ran about 20 through my chamber at the new length last night and they all extracted without marks in the moly.

 

Not good enough: drop them into the barrel by hand and see if they will spin freely. If not, you’re in the rifling. Yes, that can totally happen to hitek coated rounds without leaving extraction marks

 

15 minutes ago, jkrispies said:

What’s the benefit to the manufacturers to deviate from the norm, especially if it has the potential to limit the usability of their product?  

 

All Tanfoglio Stock 1/2/3 guns

Every CZ 75 variant

S&W M&P 9mm (all of them)

Walther PPQ & Q5 Match

 

There’s a list of guns which I have personally verified can’t take a round nose 124 out past 1.110” in most cases. You have got to verify that your particular bullet profile will load in your individual chamber - short fat round nose  bullets can’t be loaded as long as narrow pointy profiles in the same gun.

 

In the instance of the European Walther, CZ, and the Tanfoglio? Recall that SAAMI is a North Amerian thing. Europeans use the 9mm NATO standard, and some of those guns wind up with shorter chambers.

 

Edited November 23, 2017 by MemphisMechanic

[L9X25]

My WWB 115gr FMJ 200rd bulk packs are ~1.165 OAL and I thought that was really long.  Turns out that the max SAMMI spec for that round is 1.169.   

 

I always thought that production gun chambers would accept all SAMMI spec rounds, but not in the PCC world.  I know that my JP will, and have heard that

the Taccom barrels will too.  YMMV

[MemphisMechanic]

23 minutes ago, L9X25 said:

My WWB 115gr FMJ 200rd bulk packs are ~1.165 OAL and I thought that was really long.  Turns out that the max SAMMI spec for that round is 1.169.   

 

I always thought that production gun chambers would accept all SAMMI spec rounds, but not in the PCC world.  I know that my JP will, and have heard that

the Taccom barrels will too.  YMMV

Even guns with insanely short chambers will feed WWB at 1.160”

 

The reason for that is bullet profile. The ogive of that bullet is incredibly far back toward the case mouth, even though the tip is out there a full mile.

 

[Broncman]

My CZ scorpion has a short chamber. I run Berry's 124 hollow base thick plate and. They have to be ahorter than my pistol rounds. Accuracy is good, not checked it at 50 yards though.

[Banacek]

10 hours ago, MemphisMechanic said:

Even guns with insanely short chambers will feed WWB at 1.160”

 

The reason for that is bullet profile. The ogive of that bullet is incredibly far back toward the case mouth, even though the tip is out there a full mile.

 

 

Great diagram, what book is that out of?

[jkrispies]

12 hours ago, MemphisMechanic said:

Even guns with insanely short chambers will feed WWB at 1.160”

 

The reason for that is bullet profile. The ogive of that bullet is incredibly far back toward the case mouth, even though the tip is out there a full mile.

 

I’ll try the spin test.  Thanks for the advice!

 

Edit to add:  DAMMIT!!!!!

Edited November 23, 2017 by jkrispies

[Ofishl1]

On ‎11‎/‎22‎/‎2017 at 10:24 PM, jkrispies said:

Hmmm....   I don’t doubt this is true, but why would PCC barrels/chambers in particular be manufactured in a manner that is different from the accepted standard?  Lots of loading manuals list OAL as 1.145 - 1.150 for various loads. What’s the benefit to the manufacturers to deviate from the norm, especially if it has the potential to limit the usability of their product?  

I have measured the throat to rifling on 3 barrels at our Aero-Space inspection lab, the first KAW was sent back assuming it was cut too short, upon receiving the RMA barrel, same short dimensions, then bought a Wilson Arms barrel and used a depth gauge on that one and find the throat was cut deeper and JHPs and TCs could be loaded to 1.110 with no issue, IE (drop-spin) I don't know the answer to your question, only hard data that 3 KAW barrels (fellow competitor bought one too) were all short, or what we felt was shorter than acceptable. The Remington 115g RN will just drop in which are at SAMMI OAL of 1.110. TCs and JHP's will hit the rifling at the SAMMI OAL of 1.110

[wrench459]

On 11/21/2017 at 10:30 PM, Greg5611 said:

Thought I had a good couple of loads for my new 9mm PCC ....

 

I've got to ask the muzzle speeds with the long bbl?

Some boolits will do crazy things when they hit 1400fps.

I like solid copper.

[Greg5611]

Chrono at 1,100 fps.  I’m thinking I over crimped plated bullets.  I just ordered 124 gr JHP’s from Precision Delta and will give them a try.