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Major match ammo consideration


yekcoh
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I loaded my match ammo 147gr earlier this year tuned for my platform to run at 920FPS in Las Vegas (2000ft above sea) at relatively high temperature 90F+

I changed my platform to another gun and the ammo was clocking in at 870FPS, which makes sense because it's a shorter barrel...

 

I am shooting area 1 this weekend in Seattle where it's nearly 0 ft sea level and will be significantly colder than Las Vegas.

Knowing altitude and temperature play a big role in muzzle velocity... should I develop a load to give some more safety margin or just run my ammo?

 

lower altitude means higher atm, reducing muzzle velocity..

colder temp means lower gas pressure, reducing muzzle velocity....

 

Let me know what you think

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It's going to be in the low to high 70's this weekend. I would check your ammo again. 127pf is pushing the edge. Also depends on your powder, temp sensitive? Have a good Match too, 16 stages plus chrono. 

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I wouldn’t even think of going to a major match with ammo that chrono’d below 130. I would be targeting around 133-135 PF, so I would have one less thing to get stressed about. 
 

Of course, I would be shooting mostly for fun, so if I went sub-minor at the chrono stage they would still let me shoot the match for no score, and I would still enjoy the experience. 
 

But I still couldn’t imagine leaving the house with ammo that “might” not make PF wherever I was going. 

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To make minor with a 147 bullet, the velocity must be 851 fps.  If you only run at 850, prepare to shoot for fun as that comes out to 124.95 power factor.  My preferred powder is VihtaVuori as it is not temperature sensitive which helps with the hot Michigan summers and colder fall matches. 

 

Using 3.4 grains of N320 in new brass with Winchester Small Rifle primers under Blue Bullets truncated cone at OAL of 1.15, the velocities obtained from a pair of LabRadar units at this past weekend's Michigan Sectional were 942, 943 and 942 making a comfortable 138.5 power factor. Temperature was 75 degrees and South Kent Sportsmen's Club in Dorr Michigan is 640 feet above sea level.  Gun is a Sig P320 Legion with standard 5" Barsto barrel.

 

Normal disclaimers apply, use this load data at your own risk, may run different velocity in your gun, blah, blah blah.....

 

BC

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21 hours ago, Boomstick303 said:

 

At all?  What extreme's have you tested it at?

Temperature range was 40 to 90 degrees Fahrenheit.  No significant change in velocity over the chronograph.  Most deviation was 11 fps higher and that could have been due to range pickup brass that was only tumble cleaned vs. wet tumbled or a couple more tenths of a grain from the Dillon powder thrower.

 

Now the N500 series for rifle appears to be a different story. (link)

 

BC

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18 minutes ago, Boomstick303 said:

 I have 8 Pounds of N320 I have not used because for the most part I have been happy with  Sport Pistol (which is temperature sensitive). 

 

How do you like the Sport Pistol?  How much residue does it leave in the gun?  I have 8 pounds of it as backup to the N320 which is relatively clean... the FCU cleans up in the ultrasonic cleaner and requires very little extra work after that process.

 

BC

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Shoot N320 below freezing and then tell me it's not temperature sensitive.  Sport Pistol powder is a fine alternative to N320.  That being said, by PCC loads have to function from the low 20s to 90, so I use Alliant e3.  It is clean and exhibits absolutely no temperature sensitivity in that range.

 

OP, bump your load up.  I'd want 132 with SDs good enough that the slowest in a 15 round string still made minor.  That is especially true if you use an optic.

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10 minutes ago, BillChunn said:

How do you like the Sport Pistol?  How much residue does it leave in the gun?  I have 8 pounds of it as backup to the N320 which is relatively clean... the FCU cleans up in the ultrasonic cleaner and requires very little extra work after that process.

 

It is very clean.  I really do not have much to compare it to, in that its is just about the only powder I have used.  Never used Tite Group.  Its cleaner than just about any box ammo I have used. I also use P320 and take the FCU out of the grip module and dump it into an ultrasonic sink.  Works great.  From the research I have done I believe the load data as in amount used carries over from one to the other.  You might tweak 0.1 grains one direction or the other to get your load to the exact PF for a given powder.  

 

 

18 minutes ago, zzt said:

I use Alliant e3

 

How much e3 are  you using for your PCC loads?  Are you loading 147 gr for your PCC?

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32 minutes ago, zzt said:

Shoot N320 below freezing and then tell me it's not temperature sensitive. 

 

Sorry, if it's below freezing then the match being attended will be indoors.  Yes, I do like competition but I don't like freezing my butt off....

 

YMMV

 

BC

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47 minutes ago, BillChunn said:

 

How do you like the Sport Pistol?  How much residue does it leave in the gun?  I have 8 pounds of it as backup to the N320 which is relatively clean... the FCU cleans up in the ultrasonic cleaner and requires very little extra work after that process.

 

BC

I have used both Sport Pistol and N320. My Sport Pistol loads are as clean as the N320 loads. The loads are also identical; 4.0 Gr of either powder with 124 Gr Precision delta JHP at 1.120”OAL for about 130 PF out of my original X5 with the tungsten grip module.

 

Sport Pistol is the poor man’s version of N320.

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2 hours ago, Boomstick303 said:

 

It is very clean.  I really do not have much to compare it to, in that its is just about the only powder I have used.  Never used Tite Group.  Its cleaner than just about any box ammo I have used. I also use P320 and take the FCU out of the grip module and dump it into an ultrasonic sink.  Works great.  From the research I have done I believe the load data as in amount used carries over from one to the other.  You might tweak 0.1 grains one direction or the other to get your load to the exact PF for a given powder.  

 

 

 

How much e3 are  you using for your PCC loads?  Are you loading 147 gr for your PCC?

 

3.2 gr under a 147 in a 16.1" barrel.  I save the 500 or so I have left for forward falling steel matches.

 

I'm out of 147s so I've switched to 124/125s.  I have thousands of them.  In a 5" barrel 3.7gr gets you 1100fps.  3.2 = 990 and 3.0 = 885.  All of these loads will be faster in a 16.1" barrel.  3.6 under a 124 is what I now use for outlaw steel matches.  My SCSA load is 2.6gr e3 under a 124 plated in the 16.1.  Soft, accurate and the dot hardly moves.

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On 8/4/2021 at 4:37 AM, BillChunn said:

Temperature range was 40 to 90 degrees Fahrenheit.  No significant change in velocity over the chronograph.  Most deviation was 11 fps higher and that could have been due to range pickup brass that was only tumble cleaned vs. wet tumbled or a couple more tenths of a grain from the Dillon powder thrower.

 

Now the N500 series for rifle appears to be a different story. (link)

 

BC

I use N550 in my 708 handgun and have found it very temp stable. If it does vary it isn’t enough to matter and I’m running it from the 70’s down to sometimes mid 20’s. 

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On 8/3/2021 at 8:33 AM, echotango said:

Also assuming the bullet they pull actually weighs 147gr. 

This will get you. My load for a 135gn coated bullet is 3.3gn TG and has always tun 134PF in my 1911..... went to Ryan Rocks and it made 127. Looked at the bullet weight and was 133.00. For the DG at least I've found bullets from 132gn to 136gn. Out of 100 I weighed when ingot the first batch I have 90% weigh 135 +/- .05 a grain. Now after loading 6+k I doubt it's still a 90% ratio. Switched to SNS and have found them more consistent so far.

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Im running E3 as well 3.7 under a 125 blue dont remember the OAL off the top of my head but PF has been 137-139 at my last 4 or 5 majors out of a 5" 1911 or glock 34.

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e3 is definitely cleaner than TG.  It's as clean or cleaner than N310, which IMO is the cleanest burning VV powder in pistols.  Geez, e3 is even clean in notoriously dirty blowback PCCs, even with sub-minor mouse fart loads like the one I listed above.  The only bad thing about e3 is it has always been a little harder to get than other shotshell powders.  I normally order another 8 lb. jug when I open the last.  I'm down to between 1 and 2 lb. and haven't been able to find any for over a year.

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6 hours ago, zzt said:

I'm down to between 1 and 2 lb. and haven't been able to find any for over a year.

 

 This is one of the few powders I have seen at a couple of local retailers during the crunch.  Granted only 1 lb bottles but it was on the self.  I now wish I would have bought it when I saw it.  Lmao.....

Edited by Boomstick303
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