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Major match ammo consideration


yekcoh
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On 8/2/2021 at 9:59 AM, yekcoh said:

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

 

 

What did you end up doing bro? Did you use the ammo? Reason why I am asking is because at A1 we had pretty large group reporting that Chrono reads 3-5PF low.

 

My Major load that was used in several major matches was always 171..... it chronoed at 166. Too close for comfort.

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Posted (edited)
17 hours ago, SeattleDude said:

 

 

What did you end up doing bro? Did you use the ammo? Reason why I am asking is because at A1 we had pretty large group reporting that Chrono reads 3-5PF low.

 

My Major load that was used in several major matches was always 171..... it chronoed at 166. Too close for comfort.

My buddy who shot Thur/Fri scared me by saying that a lot were getting lower muzzle velocity.

I loaded 147gr to  920 and clocked in at 906 so it wasn't a huge difference for me. So yeah a couple PF lower but not something to be concerned about

 

Edited by yekcoh
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Why is everyone so scared of being around 128/168? My match ammo ran 166/167 for my limited gun for w years straight. Didnt matter where on the east coast I was. Sure most the time it took 4 rounds and every so often it took 5 but so what? I knew 100% it would make it and the gun shot awesome. 

 

With my minor ammo I have never been able to really get a load setup that is close to 125 because I need it to make PF in 3 different guns. If I was just loading it for my 1911.... it would be right at 127PF. 

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3 hours ago, Bakerjd said:

Why is everyone so scared of being around 128/168?


Do you actually think you shoot any better or faster with 127 than with 133-135? 

 

You’re running a risk for absolutely no gain at all.

 

Edited by MemphisMechanic
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Posted (edited)
On 8/20/2021 at 4:14 AM, MemphisMechanic said:


Do you actually think you shoot any better or faster with 127 than with 133-135? 

 

You’re running a risk for absolutely no gain at all.

 

 

I don't think there is an advantage in speed necessarily. But I'd like to believe that 127PF gives an edge in confidence and accuracy.

I do play safe by staying around 130PF though

Edited by yekcoh
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127 vs 133-135 will give you zero edge in accuracy. Edge in confidence is all in your head.

 

What you Can Possibly get (and its real) is spending thousands on travel expenses and coming up on Chrono that clocks slightly slower..... and you get to shoot a Major match for Fun and No Score.

 

Loading at least 5+ PF SHOULD give you confidence that you will never fail chrono. Your gun will cycle faster more reliable. Your dot will return faster for your follow up shot.

 

But this is my personal opinion and I shoot Open with occasional CO here and there. LOL

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On 8/20/2021 at 1:48 AM, Bakerjd said:

Why is everyone so scared of being around 128/168? My match ammo ran 166/167 for my limited gun for w years straight. Didn't matter where on the east coast I was. Sure most the time it took 4 rounds and every so often it took 5 but so what? I knew 100% it would make it and the gun shot awesome. 

 

Because of the powder you may be using versus a different powder someone is using.   Obviously different powders react differently to different temperatures, humidity, altitude.  For people that do not travel and/or shoot places where temps are relatively the same you can be on the razors edge.  

 

For people who travel they have to make sure they make PF, no matter what the conditions are.  I use Sport Pistol which is a reverse temperature sensitive powder.  Meaning when temps go up velocity drops.  I lost 5-7 on my power factor shooting the same ammo in Colorado versus Florida.  To not make PF at a major you just spent $800-$1500 traveling to because you wanted to shoot as low a PF as possible makes no sense.  

 

I also think in my case, my X5 Legions run way better with a heavier recoil spring and keeping my PF around 135.  The added benefit to this is I am confident in making power factor where ever I shoot.  Its not a concern.  Everyone should test their own equipment and understand the conditions your ammo works best for them and their gun.  You found something that works for you.  That does not mean that works for everyone.  Nor does it mean everyone should be so close to PF minimums.  

 

I think on the whole the shoot as low of a PF you can is completely over blown, especially in minor.  Grip the gun  properly and train properly and PF does not matter as long as the gun runs correctly and you make PF regardless of the conditions you are shooting in.  

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9 hours ago, yekcoh said:

 

I'd like to believe that 127PF gives an edge in confidence and accuracy.


Amusingly enough, 147s in particular tend to shoot tighter groups at 25yds in many recipes when they’re fired at a higher velocity.

 

Super slow, sluggish heavy 9mm ammo typically doesn’t group as tightly. In many cases. 
 

So while you feel YOU shoot straighter without as much motivation to flinch, you may find that your gun’s shooting a much wider group than it could be. But you won’t know until you test it.

 

Velocity/powder charge is a key factor in load development: I’ll never understand why most USPSA guys pick a bullet, find what makes X power factor, and call it good. Accuracy matters, and dialing in the ammo for your particular gun is way more important than power factor.

 

I’d much rather shoot a 1.5” grouping 140PF at a distant mini popper than some softballs which group 6+ inches. ;) 

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On 8/23/2021 at 9:49 PM, MemphisMechanic said:


Amusingly enough, 147s in particular tend to shoot tighter groups at 25yds in many recipes when they’re fired at a higher velocity.

 

Super slow, sluggish heavy 9mm ammo typically doesn’t group as tightly. In many cases. 
 

So while you feel YOU shoot straighter without as much motivation to flinch, you may find that your gun’s shooting a much wider group than it could be. But you won’t know until you test it.

 

Velocity/powder charge is a key factor in load development: I’ll never understand why most USPSA guys pick a bullet, find what makes X power factor, and call it good. Accuracy matters, and dialing in the ammo for your particular gun is way more important than power factor.

 

I’d much rather shoot a 1.5” grouping 140PF at a distant mini popper than some softballs which group 6+ inches. ;) 

 

I would imagine that's just a function of pressure.  Pretty much every powder shoots more consistently at a higher pressure, and it takes powder darn near the absolute top of the burn rate chart to max out 9mm, even with heavy bullets.  Which you already know, as you're one of the people on here who posts load data using the faster powders.

 

I bet if you had the balls to risk shooting Clays, Competition, E3, Titewad, N310, etc., in your loads, you'd find they were just as good at 875 fps as they are at 1000.  But admittedly I haven't tried any but the first one with heavy bullets, because they barely cycle the slide even at max loads, and I wasn't looking to risk it.

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@twodownzero there’s also the fact that the bullet is more stable because it’s both traveling and spinning a bit faster. Along with a host of other factors I’m not sophisticated enough to calculate.

 

All I know is that the sweet spot for accuracy when it comes to heavy 9mm loads usually isn’t at the bottom of the acceptable velocity window. And I’ve worked up a quie few 9mm recipes in the past 16 years or so.

 

Edited by MemphisMechanic
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59 minutes ago, MemphisMechanic said:

@twodownzero there’s also the fact that the bullet is more stable because it’s both traveling and spinning a bit faster. Along with a host of other factors I’m not sophisticated enough to calculate.

 

All I know is that the sweet spot for accuracy when it comes to heavy 9mm loads usually isn’t at the bottom of the acceptable velocity window. And I’ve worked up a quie few 9mm recipes in the past 16 years or so.

 

 

There is no such thing as "more stable," at least not until a bullet is on the ragged edge of stability.  A bullet that is spinning faster would (theoretically at least) tend to be less accurate, as it'd magnify any flaw in the bullet that put the weight off center.  Fortunately most of the bullets we're using these days have incredible consistency, and at pistol ranges it's probably noise anyway (but that's why we have a discussion forum, because talking about minutiae is fun).

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On 8/23/2021 at 9:49 PM, MemphisMechanic said:

Amusingly enough, 147s in particular tend to shoot tighter groups at 25yds in many recipes when they’re fired at a higher velocity.

 

I found this to be true in the Sig X5 as well.

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  • 2 weeks later...
On 8/25/2021 at 6:28 AM, twodownzero said:

 

There is no such thing as "more stable," at least not until a bullet is on the ragged edge of stability.  A bullet that is spinning faster would (theoretically at least) tend to be less accurate, as it'd magnify any flaw in the bullet that put the weight off center.  Fortunately most of the bullets we're using these days have incredible consistency, and at pistol ranges it's probably noise anyway (but that's why we have a discussion forum, because talking about minutiae is fun).

 

I agree with this. There is no such thing as more stable in bullet. There is only "Is it stable or not stable. "

I'm honestly not sure what caused topics to deviate. All I wanted was some input on my situation which I think got lost in translation. It's all in the past now. 

I shot the match and I finished ok. 

 

 

Thank you all.

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  • 2 weeks later...
On 8/25/2021 at 8:28 AM, twodownzero said:

 

There is no such thing as "more stable," at least not until a bullet is on the ragged edge of stability.  A bullet that is spinning faster would (theoretically at least) tend to be less accurate, as it'd magnify any flaw in the bullet that put the weight off center.  Fortunately most of the bullets we're using these days have incredible consistency, and at pistol ranges it's probably noise anyway (but that's why we have a discussion forum, because talking about minutiae is fun).

 

On 8/25/2021 at 8:38 AM, Boomstick303 said:

 

I found this to be true in the Sig X5 as well.


You disliked my phrasing along the way, then agreed with the point I was actually making. 
 

I can dig it.

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On 9/14/2021 at 11:16 AM, MemphisMechanic said:

 


You disliked my phrasing along the way, then agreed with the point I was actually making. 
 

I can dig it.

 

You quoted two different people.

 

I suspect that loads were more accurate at higher velocities because the pressures were more consistent and that resulted in a tighter group on the paper.  The chrono would at least provide some evidence for this.

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