115 g JHP WWB – Perfect bullet design to fail in SCCY CPX-2

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115 g JHP WWB – Perfect bullet design to fail in SCCY CPX-2

Postby Quixote2 » Sat Mar 21, 2015 1:24 pm

If you read my posts on 9mm steel cased ammunition: viewtopic.php?f=8&t=16746&view=unread#unread ; I found problems with the 115 g Winchester White Box JHP ammunition.

This post reports the results of my examination of my SCCY CPX-2 serial number 196xxx with assorted ammunition and my conclusions.

I examined cartridge dimensions and shape for WWB FMJ, WWB JHP, and Critical Defense JHP that had operated with no problems. The WWB JHP is shorter than the WWB FMJ (27.6 mm vs 29.5 mm) and approximately the same length as the Critical Defense (27.2 mm). The WWB JHP also has a larger diameter sharp copper lip around the “hollow point” than the Critical Defense round (5.25 mm for WWB and 4.18 mm for the Critical Defense). A "casual" (eyeball) examination of the WWB JHP and FMJ bullet profiles appear to be identical shape except for the truncated tip. The relocated weight from the JHP truncated tip and hollow cavity would result in the bullet being seated deeper into the cartridge casing than the identical weight FMP bullet.

With the disassembled CPX-2 slide, barrel and a fired cartridge case I concluded that the design and tolerances in the CPX-2 result in interferences between the fired cartridge case being ejected and the next round of WWB JHP in the magazine.

The slide for the CPX-2 has an about 1/10 inch wide rail in the center of the rear half of the slide. This “magazine cartridge compression rail” is tapered from near zero height at the rear of the slide to about 1/10 “ high terminating at the bolt face. This rail can be felt as additional resistance at the final 1/10 inch insertion when you insert a loaded magazine into the pistol. The rail is pushing the cartridge column down into the magazine and providing vertical orientation of the top cartridge to the slide.

1) When the slide feeds a cartridge into the barrel, the “magazine cartridge rail” on the slide pushes the base of the top cartridge forward to the barrel ramp and into the barrel.
2) When the top cartridge clears the magazine, the next cartridge in the magazine raises and is confined by the slide “magazine cartridge rail”
3) As the slide move forward chambering the first round, friction between the 2nd cartridge at the top of the magazine and the slide “magazine cartridge rail” slides the magazine cartridge forward to contact with the barrel ramp.
4) The shorter WWB JHP is supported only about ¼ the distance from the rear by the magazine lips.
5) The final movement of the barrel is controlled by the L-V shaped pin groove in the barrel that ramps the barrel up into the “locked” firing position.
6) This barrel moving up appears to actually rock or pivot the next round in the magazine up slightly. The barrel pushing up on the cartridge tip while rocking around the rearward support on the magazine lips.
7) The slide “magazine cartridge rail” tapered ramp is relieved at the final 5/16 inch to parallel the axis of the slide. Thus the final 5/16 inch flat bears only on the cartridge bullet (tapering to the front of the cartridge) and emphasizes by allowing increased potential cocking up of the next cartridge in the magazine awaiting discharge of the pistol.
8) When the pistol is fired, the barrel pin mechanism unlocks and pivots the barrel down as the initial movement.
9) This barrel pivoting down pushes the fired cartridge down across the bolt face in the slide by means of a lug above the barrel chamber.
10) The initial vertical movement of the fired cartridge also moves the lip of the fired cartridge below the bottom of the slide “magazine cartridge rail”.
11) This point of barrel/slide movement leaves the fired cartridge in perfect position to catch the sharp copper lip of the next cartridge in the magazine that was oriented as described through step 7.
12) Continued rearward movement of the slide and extractor moving the fired cartridge catches the magazine cartridge by the hollow point lip and moves the cartridge to the rear of the magazine.
13) When the magazine cartridge hits the rear of the magazine, the column of cartridges stops moving and the extractor is demounted from the fired cartridge with the cartridge partially extracted from the chamber.
14) The slide proceeds to the rear with the slide “magazine cartridge rail” clearing the magazine stack.
15) The magazine stack rises and the slide “magazine cartridge rail” captures/catches the rear face of the top cartridge.
16) The top magazine cartridge moves forward and runs into the previously fired cartridge that was left in the pistol. We have a combined FTE (Failure To Eject) and FTF (Failure to Feed).

I examined cartridge dimensions and shape for WWB FMJ, WWB JHP, and Critical Defense JHP that had operated with no problems. The WWB JHP and Critical Defense are both shorter than both the WWB FMJ. The WWB JHP also has a larger diameter sharp copper lip around the “hollow point” than the Critical Defense round.

With the disassembled CPX-2 slide, barrel and a fired cartridge case I concluded that the design and tolerances in the CPX-2 result in interferences between the fired cartridge case being ejected and the next round in the magazine for 115 grain JHP WWB. The gun design and tolerances result in interferences with different bullet shapes and cartridge total lengths make the 115 g WWB JHP unacceptable for use with the SCCY CPX-2. The stacked up tolerances and bullet design are apparently within thousands of an inch as about 50% of the final attempts worked/failed.

It may be possible to redesign the CPX-2 slide “magazine cartridge rail” and magazine lips to make use of the 115 grain JHP WWB acceptable. The easiest way is to avoid use of WWB JHP in the SCCY CPX-2 and to examine the bullet profile of other JHP ammunition to avoid the large diameter hollow point hole so that the bullet design/profile approximates the Hornady Critical Defense design. Total cartridge length may also be important.
Last edited by Quixote2 on Mon Mar 23, 2015 2:59 pm, edited 2 times in total.
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby smokersteve » Sat Mar 21, 2015 5:40 pm

My CPX2 serial # 166xxx does fine on WWB jhp
Glock 19
CPX-2 FDE
S&W Shield 9mm
Kahr CM9
Kahr CW380
S&W M&P22
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby tripleb » Sat Mar 21, 2015 7:01 pm

Quixote2, I for one appreciate your comments and attention to detail ... keep up the GREAT work. I have not fired any WWB JHP ammo through my CPX-2TT. The only true hollow points I have fired are these and they functioned well:

http://www.midwayusa.com/product/368650/copper-only-projectiles-cop-ammunition-9mm-luger-p-115-grain-solid-copper-hollow-point-lead-free-box-of-25?cm_vc=ProductFinding BTW, not the +P version.

I have also shot 115gr. Hornady Critical Defense without issue.
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby getvicious » Sat Mar 21, 2015 10:37 pm

I've fired several brands of hollow point ammo thru mine, including WWB JHP (147 grain) all without issue.
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby wrearick » Tue Mar 24, 2015 2:45 pm

Thank you for your efforts to determine the cause of the problem instead of offering up a back handed, unsubstantiated, opinion on the cause. Definitely will make me try some of the WWB before I buy a bunch at any price.
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby Mrbone » Tue Mar 24, 2015 7:14 pm

I've put several hundred rounds of wwb through mine without any problems at all. The problem is these guns aren't uniform at all. Total hit or miss. Some people's are perfect some are junk. My current cpx has 700 rounds or so with only a snapped ejector.
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby getvicious » Tue Mar 24, 2015 10:35 pm

wrearick wrote:Thank you for your efforts to determine the cause of the problem instead of offering up a back handed, unsubstantiated, opinion on the cause. Definitely will make me try some of the WWB before I buy a bunch at any price.

That's a good idea before buying a bunch of any ammo. Not all ammo works the same in all pistols. Find what works well in your pistol then buy a bunch of that. Avoid what doesn't work well.
It's not the blast that kills you - It's the tumble to the bottom of the 800 foot crater.....
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby mogunner » Sat Mar 28, 2015 5:59 pm

I've shot Fiocchi FMJ 115gr, Federal Champion 115gr FMJ, American Eagle 124gr FMJ, Winchester PDX-1 bonded 124gr JHP's, Remington 115gr JHP's and my handloads of 115gr plated round nose and 115gr Hornady XTP JHP's through my CPX-2 with absolutely no failures of any kind. I presently have 820 round total through the pistol since new.
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby Quixote2 » Mon Mar 30, 2015 6:58 pm

Well, I want to report that SCCY took care of my concerns. Last last week I called SCCY and got routed to Jason. After I described my problem, he volunteered to send me a replacement slide with an enclosed label to mail back the original.

Today, about 3:00 PM the mail came, I did a cursory inspection and installed the slide. I called my shooting buddy that is interested in the CPX-2 and he wanted to come along to observe the test and to shoot some of his ammo to get a feel for the trigger pull.

The test was a success, I ran two magazines, 20 rounds of WWB 115 g JHP with no errors. My friend then ran 20 rounds of his ammo (?) with no failures. As this was just an operability test we went home. Approaching 300 rounds total through the CPX-2, My friend now acts like he is trying to talk himself out of buying yet another pistol.

A success all the way around with thanks and praise to the SCCY customer relations (Jason).
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby Lovin' it » Wed May 20, 2015 5:37 pm

I am surprised that no one mentions issues -or even usage- of Blazer Brass 115 FMJ as an issue. I am a new carry owner and decided to give the CPX-2 a try. I shoot at a fantastic new range in Waukegan, IL - GTR Sports and after firing 1/2 mags of BB 115 I started getting FTE and jamming. I bought this ammo because the casing sent with my new CPX-2 was a Blazer Brass.

After the first mag, the jamming got worse. My Range Officer, Chick Buruffi (30 years experience and with support from the resident gunsmith) determined that as the fired casing was ejecting, the floating barrel was sending it down to jam the upcoming round.
Chick loaded some reloads, some range rounds and even some Walmart loads (name unpronounceble by the gunsmith) and all fed flawlessly.

Has anyone had good experiences with Blazer Brass in his CPX-2? Or bigger issues?
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby Lovin' it » Thu May 21, 2015 8:29 pm

OK boys-I went to Gander this morning and bought 50 "Lawman" and 50 Remington 115 gr, FMJ. When I took a round out of the box, the round looked perceptibly shorter than the Blazer Brass that was hanging up as often as 5 out of a mag of 10. Guess what?

100 out of 100 -no hang-ups, FTE/FTF. I am going to keep trying other manufacturers, but Blazer is no longer on my list of ammo for my CPX-2.

I finally feel like I can carry this pistol without worry, but will keep being on my toes.
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby getvicious » Thu May 21, 2015 9:40 pm

There's a pretty wide range in overall length a round can be and still meet SAAMI specs.

The 9mm Luger can be between 1.000 inch and 1.169 inch long and be within specs. .169 doesn't sound like much but put it in perspective - .125 is 1/8th inch. So, a little more than 1/8th inch is the tolerance (actually closer to 11/64ths inch).

Yours obviously likes the ammo on the short end of the spec. Find what works then use that.
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Re: 115 g JHP WWB – Perfect bullet design to fail in SCCY CP

Postby MARINE DIVISION TWO » Fri May 22, 2015 2:22 am

I will accept all WWB ammo that you feel is not working in the SCCY CPX 2 guns ! My SCCY has been eating them for over 1,400 rounds not one issue,And Federal 147 gr JHP another 250 rounds and again no issue.Just P M me and I will give you a forwarding address for all your WWB ! JMO/MDT
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