BIG BORE PX4 Match Review.

[P.E. Kelley]

I will look for his article. I will also research this. I've got the "gots to know" bug now, too.

I don't see how a spiraling bullet would move left or right if a spiraling barrel were to move or not. That bullet is going nearly 600 miles per hour and the barrel... not so fast. Everything is still in straight alignment, spiral or not. It will be challenging to figure this mystery out!

Quote from the article 'At first I thought it was me, and I checked myself by switching to a high-end 9mm target gun I had along on the same range trip: five shots into just over an inch at the same distance. So back to the PX4 Storm in .45 ACP I went: a five-inch group. Ouch. Out of equal parts frustration and desperation, I tried some high-speed hollowpoints. Wow. Five shots of Black Hills 185-grain JHPs went into three inches on the first group, and once I’d gotten accustomed to the brisker recoil, I could do better than that all the time.

Why the difference? I can only speculate. Rotating-barrel designs use barrel rotation counter to the torque created by the bullet engaging the rifling. (Barrel rotates left, torque pushes right, or vice-versa.) If the bullet is slow, the barrel may have time to rotate enough to change the fit of the barrel muzzle to the slide opening. Or not."



Read more: http://www.handgunsmag.com/reviews/f...#ixzz5Ic7ZEtET

[PX4 Storm Tracker]

Quote from the article 'At first I thought it was me, and I checked myself by switching to a high-end 9mm target gun I had along on the same range trip: five shots into just over an inch at the same distance. So back to the PX4 Storm in .45 ACP I went: a five-inch group. Ouch. Out of equal parts frustration and desperation, I tried some high-speed hollowpoints. Wow. Five shots of Black Hills 185-grain JHPs went into three inches on the first group, and once I’d gotten accustomed to the brisker recoil, I could do better than that all the time.

Why the difference? I can only speculate. Rotating-barrel designs use barrel rotation counter to the torque created by the bullet engaging the rifling. (Barrel rotates left, torque pushes right, or vice-versa.) If the bullet is slow, the barrel may have time to rotate enough to change the fit of the barrel muzzle to the slide opening. Or not."



Read more: http://www.handgunsmag.com/reviews/f...#ixzz5Ic7ZEtET

Yes, thanks! I had already found the article and was studying it. I am going to study more into this conclusion he wrote of.

[JAD]

If you think so, you might enjoy review of some of the threads associated with the M&P 9mm’s awful accuracy with lots of different bullets. As I recall, a very cogent explanation was given by Randy Lee of why the 9 was problematic but not the major caliber guns. It had a lot to do with bullet weight and dwell time.

[P.E. Kelley]

If you think so, you might enjoy review of some of the threads associated with the M&P 9mm’s awful accuracy with lots of different bullets. As I recall, a very cogent explanation was given by Randy Lee of why the 9 was problematic but not the major caliber guns. It had a lot to do with bullet weight and dwell time.

Thanks, I was thinking about that very issue. "Solved locally" with KKM barrels, but root cause? I don't know.

[DAB]

yep, G levers (decocking only) are the way to go. gun is always ready to go. easy swap out.

[beenalongtime]

45 is big...right?

I really liked this ballistic tool and it likes 185 grain bullets...hates 230's!

Owner of my LGS has been trying to get me into forty fives. My PX4, is my defense choice and they don't make a 10mm, which was a "want because it was what I was originally taught on", so your pushing me even more towards acquiring a sample of this. Seems logical to do so with the same controls, etc. for training benefit. (and I would have a while back, but missed a D slide version as it went out of stock, in the cart)
I'd love to see a non out of box review and get your opinion of one with a LTJIAB.

"Eight six seven five three 0 nine." That made my day. Another great review. I enjoy how you present information while having fun.

Have to agree with farscott on this.

[arcfide]

I commented on the video, but I'll comment here as well. My Px4 9mm exhibited a similar strange hatred of certain rounds. in my case, it's only one round, the 115gr Tac-XP Black Hills. I can't even get it to print into an 8" circle at 25 yards (the same ammo does 2 - 2.5" groups in my APX) because it shoots so far left and wild. Every other bullet though, in all the bullet weights I've tried, and they go right where I want them, in the 2" group size range.

[PX4 Storm Tracker]

Another possible consideration is if the bores from some earlier PX4s were slightly larger.

When a cartridge is fired, the rear of the bullet moves before the front. This causes the bullet to "slug out" and fill the grooves. If a lower pressure cartridge is ignited in a bore that is larger it might not slug out as tightly and therefore have less accuracy and less consistency. The lighter bullets are driven by a more velocity producing charge and slug out better, being more accurate.

This could also affect brands with harder lead projectiles.

Recovering fired slugs to compare rifling marks is one way to check that.

[P.E. Kelley]

Another possible consideration is if the bores from some earlier PX4s were slightly larger.

When a cartridge is fired, the rear of the bullet moves before the front. This causes the bullet to "slug out" and fill the grooves. If a lower pressure cartridge is ignited in a bore that is larger it might not slug out as tightly and therefore have less accuracy and less consistency. The lighter bullets are driven by a more velocity producing charge and slug out better, being more accurate.

This could also affect brands with harder lead projectiles.

Recovering fired slugs to compare rifling marks is one way to check that.

"Obturation" for bullet upset to fit the bore is the term I am familiar with.

And a bunch would need to occur in this case...

[PX4 Storm Tracker]

"Obturation" for bullet upset to fit the bore is the term I am familiar with.

And a bunch would need to occur in this case...

Wow... indeed it would!