Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
PSA
Member Login

Site Notices
Posted: 8/22/2015 8:21:56 PM EDT
So the other weekend (been about 2 weeks now) i went out shooting with a couple buddies. And I started to notice some issues with some 9mm loads I had made. The other previous outings I hadn't noticed this issue. The loads were shooting about 2-3inches high out to 30yards.

9mm
124gr Plated Bullet
Win Primers
3.9gr of Bullseye.

I ran the bullets through an XD9, Taurus Slim, G17 and Ruger SR9c. They all shot high, maybe I hadn't noticed it on the prior outings, but I need a little help figuring it out. I started thinking about tuning the load down a little, but then I examined my loads against some buddies reloads and some factory ammo. It seems I put a bit of a heavy crimp on them. Does the crimp really mess with the accuracy that much? Or could it be the powder?

Thanks,
Link Posted: 8/22/2015 8:37:34 PM EDT
It may be that your heavier crimp allowed the pressure to go up in those rounds, causing the velocity to go higher.  Faster bullets hit higher.  It's not accuracy, it's a different velocity.
Link Posted: 8/22/2015 9:16:13 PM EDT
Are the rounds impacting high compared to factory ammo or the same ammo only thing that changed was the crimp. I don't know if your "accuracy" was effected but point of aim point of impact. I've found to be linked to velocity. Its not a problem if you know your holdovers.
For example all ammo shot at 25 yards, with the same gun, same day, same sights. All ammo makes uspsa minor power factor (130) for their weight. Only changes are the ammo:

115= poi is poa
124= poi is 1.5 inches high
130= poi is 2.25 inches high
147= poi is 3 inches high
165= poi is 4 inches high

To me your load data sounds a little low. I thought that with a 124 grain bullet and Bullseye powder you would have needed at least 4.2 grain to make at least 1050 FPS. Do you have a chrono?
Link Posted: 8/25/2015 7:19:06 PM EDT
No I don't have a chrono, I'm trying to get ahold of one but no luck so far. I will say they shoot ok, sometimes they feel a bit more stiff compared to a factory 115gr.
Link Posted: 8/25/2015 7:24:13 PM EDT
Was this off a rest/sandbag/Ransom Rest, or off hand?
Link Posted: 8/25/2015 7:51:09 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Freestyle1138:
No I don't have a chrono, I'm trying to get ahold of one but no luck so far. I will say they shoot ok, sometimes they feel a bit more stiff compared to a factory 115gr.
View Quote

"Stiff" recoil goes with higher pressure and velocity.  I'm betting your rounds are just going quite a bit faster than the factory/other loads you've been used to.
Link Posted: 8/26/2015 12:04:38 AM EDT
Link Posted: 8/26/2015 1:28:08 AM EDT
I'm having the opposite problem with my Lee 124gr. I use either 3.5 or 4.0gr of Bullseye and both shoot low from my Ruger P89. I don't know about you but I'd rather have it shooting high than low. I'm not not going to be changing bullet molds so it looks like I'll be looking for an adjustable rear sight for my P89.

Motor
Link Posted: 8/26/2015 8:04:03 AM EDT
[Last Edit: 8/26/2015 8:07:27 AM EDT by ironhead7544]
That is why some pistols have adjustable sights.  

With fixed sights, it is possible to zero the pistol just by changing powder, powder charge or bullet type.  

It will be a trial and error thing.  

For a self defense pistol, I zero with the defense load and then find a lighter handload that will hit the same point of aim for practice.

In general, if the pistol is sighted for 115 gr loads it may shoot a little higher with 124 gr loads.   Not enough difference to matter at self defense ranges.

Crimp will not effect the velocity very much on the 9mm.
Link Posted: 8/26/2015 5:41:18 PM EDT
As others stated the crimp is increasing the pressure. Faster means a flatter trajectory making them hit higher.

Also, the added recoil ( from higher pressure) is raising the muzzle up before the bullet exits, resulting in a higher POI.

Reduce the charge and lighten up the crimp, it should drop the POI enough.
Link Posted: 8/28/2015 8:12:52 PM EDT
Thanks for the info. I'm going to start by reducing the crimp. And i'm really trying to get a chrono, but none of my friends seem to have a working one.
Link Posted: 8/28/2015 8:34:17 PM EDT

With a handgun a faster load hit low, and a slower load hits high.
It is the result of the faster round leaving the barrel sooner in the recoil/muzzle flip.
Link Posted: 8/28/2015 9:23:40 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By pepperbelly:

With a handgun a faster load hit low, and a slower load hits high.
It is the result of the faster round leaving the barrel sooner in the recoil/muzzle flip.
View Quote

I think you're a little off there.  It doesn't matter if it's a pistol or rifle round, faster rounds hit higher than slower rounds with the same point of aim.  It's about gravity, nothing else.
Link Posted: 8/28/2015 10:00:27 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:

I think you're a little off there.  It doesn't matter if it's a pistol or rifle round, faster rounds hit higher than slower rounds with the same point of aim.  It's about gravity, nothing else.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:
Originally Posted By pepperbelly:

With a handgun a faster load hit low, and a slower load hits high.
It is the result of the faster round leaving the barrel sooner in the recoil/muzzle flip.

I think you're a little off there.  It doesn't matter if it's a pistol or rifle round, faster rounds hit higher than slower rounds with the same point of aim.  It's about gravity, nothing else.


With a rifle you are correct, but not with a handgun.
Link Posted: 8/29/2015 8:32:12 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By pepperbelly:


With a rifle you are correct, but not with a handgun.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By pepperbelly:
Originally Posted By GHPorter:
Originally Posted By pepperbelly:

With a handgun a faster load hit low, and a slower load hits high.
It is the result of the faster round leaving the barrel sooner in the recoil/muzzle flip.

I think you're a little off there.  It doesn't matter if it's a pistol or rifle round, faster rounds hit higher than slower rounds with the same point of aim.  It's about gravity, nothing else.


With a rifle you are correct, but not with a handgun.

Please explain how handgun bullets fall "up."  Trajectories are trajectories, it doesn't matter whether the bullet is fired from a rifle or pistol.

This is a handgun trajectory graph.

The only thing different from a rifle trajectory graph would be the specific velocities involved.
Link Posted: 8/29/2015 1:26:30 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:

Please explain how handgun bullets fall "up."  Trajectories are trajectories, it doesn't matter whether the bullet is fired from a rifle or pistol.

This is a handgun trajectory graph.
https://www.shootersforum.com/attachments/tech-notes/8599d1246579080-handgun-hunting-loads-critical-view-trajectory.jpg
The only thing different from a rifle trajectory graph would be the specific velocities involved.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:
Originally Posted By pepperbelly:
Originally Posted By GHPorter:
Originally Posted By pepperbelly:

With a handgun a faster load hit low, and a slower load hits high.
It is the result of the faster round leaving the barrel sooner in the recoil/muzzle flip.

I think you're a little off there.  It doesn't matter if it's a pistol or rifle round, faster rounds hit higher than slower rounds with the same point of aim.  It's about gravity, nothing else.


With a rifle you are correct, but not with a handgun.

Please explain how handgun bullets fall "up."  Trajectories are trajectories, it doesn't matter whether the bullet is fired from a rifle or pistol.

This is a handgun trajectory graph.
https://www.shootersforum.com/attachments/tech-notes/8599d1246579080-handgun-hunting-loads-critical-view-trajectory.jpg
The only thing different from a rifle trajectory graph would be the specific velocities involved.


It has nothing to do with the trajectory. When you fire a handgun the pistol causes the muzzle to flip up. The faster round leaves the barrel when it is pointed lower. The slower bullet leaves when the muzzle is pointed slightly higher.


Link Posted: 8/30/2015 11:23:25 AM EDT
Bullets begin to fall when they leave the barrel.  Faster bullets fall less in the same distance.  Muzzle flip has nothing to do with it.
Link Posted: 8/30/2015 5:13:07 PM EDT
[Last Edit: 8/30/2015 5:19:52 PM EDT by HighpowerRifleBrony]



Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:




Bullets begin to fall when they leave the barrel.  Faster bullets fall less in the same distance.  Muzzle flip has nothing to do with it.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:




Bullets begin to fall when they leave the barrel.  Faster bullets fall less in the same distance.  Muzzle flip has nothing to do with it.



It is my observation that heavies impact lower when fired from rifles, and though the results are skewed due to different powder charges, impact higher when fired from a pistol.





The Fall Bullseye league is coming up. I may try 185s and 230s out of my M1991 and note the differences.
However this is interesting:






http://riflemansjournal.blogspot.com/2009/05/30-caliber-riflemen.html
An analysis of many years of plot sheets from 600 to 1000 yard matches
shows that I, like many shooters, tend to lose points to shots "in the
corners” at 2:00 or 10:00. These shots are not simply the innocent
byproduct of a poorly timed pulse beat and an unseen gust of wind; they
are most frequently the result of the muzzle moving in that direction
just as the shot breaks – even if that movement is within the X ring.
These plot sheets also show that these corner shots happen far less
frequently with cartridges such as the 6BR and 6XC than with the .308
and .30-06. Do we move less when shooting small calibers? No, of course
not. The real culprit is the amount of muzzle movement after the shot
breaks but before the bullet clears the muzzle. This is barrel movement
during barrel time (BMBT). BMBT tends to carry the muzzle in the
direction in which it was moving when the shot broke. How far it carries
the muzzle is the salient point of this discussion.






http://riflemansjournal.blogspot.com.es/2011/04/cartridges-sibling-rivalry-308-vs-30-06.html






Compared to the .308, with the same bullet weight, you feel more
pressure from the handstop, but not particularly more in the shoulder.
The more significant difference is the amount of muzzle movement during
barrel time; when the shot breaks while the barrel is still moving, the
.30-06 will usually deliver the shot a bit further from center than the
.308 which has less muzzle movement. As long as the shot is broken with a
still muzzle and with good follow-through, the increased muzzle
movement during barrel time won't be a problem. Uncomfortable
recoil isn't a concern, but the need for highly refined shot execution
skills is both the limitation and the opportunity presented by the
.30-06.


ETA: I think it comes down to how the firearm is fixed in place. Hands aren't likely as firm as a sling and shoulder, but even a shoulder has some give compared to a vice/rail gun setup.




 

 
Link Posted: 8/30/2015 8:03:21 PM EDT
I agree that how the firearm is placed and fixed on a bench has a lot to do with the amount of rise you get.  But velocity determines drop, period.  Once the bullet leaves the barrel, it starts falling (admittedly from an upward arc due to the way sights work), and the faster it goes, the less time it has to fall.  With a pistol round, the bullet has left the barrel before the slide begins moving, with muzzle flip coming after that.  

A POI difference of several inches at 30 feet points to a substantial difference in MV, and I'd be interested in whether the OP noticed any pressure signs with those rounds that impacted higher.
Top Top