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Just an FYI.  Was working up load for new open gun.   Precision Delta 124 JHP we’re running around 60 FPS faster than 124 CMJ Montana Golds from the same gun and same powder charge.  No difference in accuracy.

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What about COAL and bullet profile?  (i.e. is the Precision Delta bullet longer than the Montana Gold bullet?)  Does the Precision Delta bullet sit deeper into the case, reducing powder capacity?  If powder capacity is decreased, it wouldn't have to be a whole lot to increase velocity with the same COAL.

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@45 Raven MGs jacket alloy is harder, so a little bit more gas gets by before it seals tightly to the bore.

 

The same velocity difference is seem in production minor loads, where 1.110” vs 1.130” often has no appreciable velocity difference

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For me, same load with 115 jhp, MG were faster out of 2 guns than PD by ~40fps

Edited by echotango

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115 an 124 pd are faster in both my open gun. About same 35fps

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With N320 and 124gr MG JHP, a difference in OAL of .02 was about the same as the difference on .1gr of powder in terms of velocity in a test I conducted  across a range of 0.100 for OAL.

I have not tested other bullets and powders across that wide a range, but with faster burning powders at 9mm minor velocities, that has been a reliable predictor for other powders and bullets.

As to the specific question, I have data for the MG 124gr JHP vs the PD 124gr JHP with only two powders.   With N320, the PD was about 30 feet/sec faster.  With Titegroup, it was 10.


Softer bullets obturate better and seal in more gas.  It makes sense to me that PD would be faster than MG, with MG being a harder bullet.


 

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124 jhp   PD vs MG same powder charge .   Less than 5 fps difference in my open gun.

Edited by AHI
reversed pd

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11 hours ago, IDescribe said:


Softer bullets obturate better and seal in more gas. 
 

 

Mmhm. ;)
PD's stepped base may also aid in obturation. 

The differences in jacket can play a part as well.  There is more copper (less alloy) in a PD jacket.  While this material is more expensive, and doesn't "shine" like a higher alloy jacket, we believe it is the right choice for sporting projectiles. 
 

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1 hour ago, Ssanders224 said:

 

Mmhm. ;)
PD's stepped base may also aid in obturation. 

The differences in jacket can play a part as well.  There is more copper (less alloy) in a PD jacket.  While this material is more expensive, and doesn't "shine" like a higher alloy jacket, we believe it is the right choice for sporting projectiles. 
 

 

I was thinking of softer jacket but said softer bullet.   The MG jacket is indeed harder metal. 

 

 

 

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I used to shoot DP JHP and switched to MG CMJ. Same OAL of 1.168 with same 7.6gr of Silhouette.

 

DP JHP - 1404 fps

MG CMJ - 1393 fps

 

Same zero on both bullets out of my Atlas Chaos.

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On 12/2/2018 at 11:01 PM, IDescribe said:

Softer bullets obturate better and seal in more gas. 

Darnit, I wanted an excuse to drop that word into a sentence.

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On 12/2/2018 at 6:05 PM, echotango said:

For me, same load with 115 jhp, MG were faster out of 2 guns than PD by ~40fps

Same here. PD’s  slower than MG AND MG are already slow!😊

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Long time MG user and switched to Everglades Ammunition, same powder charge was faster than normal load. Just as accurate if not better and cheaper. Cannot say the same thing for PD. 

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37 minutes ago, Shadyscott999 said:

PD are 40 fps second faster for me that MG not to mention cheaper and as accurate as anything I have ever tried.  

Same for me pd 40 fps faster in two guns than  mg

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In my 2 open supers , one a govt slide and the other a shorty, I tried PD, MG, & Zero HP's with different powders and found a negligible velocity difference with the Zero & PD and MG slightly slower with all powders used (A#7, 3N38, Autocomp, & Sil). The recoil impulse was also consistent with each bullet within a specific powder. As far as accuracy they were again all equal. I encountered the same results in my M&P9 with a KKM barrel within the powder range for that gun.

I didnt notice you mentioning what handgun your shooting so I will round off my experience and feelings on the bullet discussion in a handgun. A 30-40 fps difference between a bullet brand is a .1-.2 grain difference within most pistol powder and its not gonna effect feel or cost enough to fixate on it. Also found that higher end barrels (Schuemann, KKM, Bar-Sto etc) tend to perform with most bullets pretty consistently. So bullet choice becomes less of a concern with reputable offerings. Some brand  OEM production barrels do have the potential to be more picky with projectile choice so it could however be a concern with "stock" guns. But remember in the handgun practical world a 1/4-1/2 difference in group size say at 20 yards doesn't mean much so dont get to caught up in that. Be more concerned with powder for the desired velocity and how it correlates to recoil impulse your looking for moreover than the bullet, thats gonna greatly improve your shooting vs which bullet shoots a 1/2 tighter group etc. Then the cost of said bullet, the less you spend means the more you can buy and the more you will shoot, again improving your ability. So in conclusion, by all means test bullets and try a few different powders, determine if any one bullet out shoots another by considerable margin in your gun. If they all run close then choose the more cost effective bullet and focus on what powder makes it feel best.   

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