Punching Above Weight

[PappaWheelie]

The months-long absence of replacement RAMI recoil spring assemblies and the encountering of an experience documented on czfirearms.us of premature spring failure http://www.czfirearms.us/index.php?topic=95795.msg736672#msg736672 led me to seek a fresh springpack for carry.

Soon after procuring stiffer DPM Systems Technologies Recoil Reduction springs for my RAMI, CZ-USA announced (last evening) that the RAMI springpack was back in stock. I suspect CZUB acted responsibly to my mild emailed rebuke http://www.czfirearms.us/index.php?topic=96403.msg741982#msg741982 in expediting inventories.

I've ordered three springpacks, which I'll use for target practice when my current springpack does fail, but for concealed carry duty I'll use the stiffer DPM springs http://www.czforum.com/forum/index.php?topic=5506.msg23220#msg23220 to manage the Underwood +P+ 90 grain Xtreme Defender ammo that represents current state-of-the-art (for both quality and performance, imho) short barrel ammo.

Short barrels limit muzzle energy, so require increased pressure ammos to perform like full-size pistols.
Increased pressure ammos require stiffer recoil springs to avoid adverse impact effects. http://www.czforum.com/forum/index.php?topic=5424.msg22926#msg22926

The combination of the Underwood ammo and the DPM springpack means my Invisible 15 Round (2.93" barrel Subcompact) RAMI BD will be "punching above weight" without hardware duress, a "lines in pleasant places" result that seems to have been orchestrated from above. Every good and perfect gift..., A man can receive nothing..., what do you have that you didn't receive?

That's a TYJ!

[czsuby]

Nice write up!  Thanks.

[GBUS]

Thankfully ammo manufacturers are using better technology and now manufacture bullets designed to work efficiently in shorter barrels and at lower velocities, so there's really no need to pound your gun with +P+ pressure loadings these days.

[dannyvi]

Right, Pappawheelie! I also have the DPM springs on my 97BD. I rotate the Rami DPM aprings between my 9mm and .357 Sig Rami.

[PappaWheelie]

Thankfully ammo manufacturers are using better technology and now manufacture bullets designed to work efficiently in shorter barrels and at lower velocities, so there's really no need to pound your gun with +P+ pressure loadings these days.

Hi GBUS,
The whole point of the post is my joy at both not being underpowered ("lower velocities") b/c of an ultimately concealable Subcompact barrel length, http://www.czfirearms.us/index.php?topic=81829.0
AND the fact that with appropriately stiffer recoil springs to handle the "+P+ pressure loadings," my gun does NOT get pounded.

Reference again (in case you missed it), https://cajungunworks.com/how-to-select-the-proper-recoil-spring/

Any ammo pressure level has a correspondingly appropriate recoil spring stiffness to regulate impact velocity to optimum for spent casing discharge distance, a common-to-all measure of impact velocity.

Congrats, btw, on your pretty new RAMI BD!

[GBUS]

I understand what you are saying, but are you really underpowered if the bullet is reaching full expansion at the desired penetration depth and doing it with standard or +P pressures.

I'd rather have a bullet that penetrates the 12-15" and expands completely and gives lower recoil over one that does the same thing but with a harsher +P+ recoil pulse.
Now if you are looking for specific barrier penetration rounds or will be encountering extremely heavy clothing etc.... Then sure you may need a round with that design factor in mind and that may include higher working pressures and +P+ designation.

[eastman]

Since there is no SAAMI spec, you have no idea what a manufacturer really means when they call something +P+. Only 4 cartridges have an actually defined +P rating (.38 Special, .38 Super, 9x19 mm and .45 ACP).

The manufacturers can very easily say you voided the warranty by firing +P+ ammo.

[PappaWheelie]

I understand what you are saying, but are you really underpowered if the bullet is reaching full expansion at the desired penetration depth and doing it with standard or +P pressures.

I'd rather have a bullet that penetrates the 12-15" and expands completely and gives lower recoil over one that does the same thing but with a harsher +P+ recoil pulse.
Now if you are looking for specific barrier penetration rounds or will be encountering extremely heavy clothing etc.... Then sure you may need a round with that design factor in mind and that may include higher working pressures and +P+ designation.

Hi again GBUS,

The Underwood Xtreme Defender bullet is a new-technology non-expanding approach that uses outwardly curved channels to create hydraulic slicing that reaches further, in terms of permanent wound channel size, than any expanding hollow point technology bullets. The Xtreme Defender is a lower mass variant of its Xtreme Penetrator predecessor, in interest of velocity (and thus muzzle energy) maximization with penetration preservation.

Its rated velocity, 1550 fps, corresponds to full-size pistol testing, and its penetration, rated at 16 inches, is also lowered by short barrel pressure limitation, so is likely right in your 12-15" favored range with which I fully agree.

The RAMI's slide mass, aluminum frame, and low bore center combine to produce industry-enviably low recoil, and the DPM Systems Technologies springs have as well established themselves as effective in minimizing recoil, something that I've begun to believe is predominantly a result of slide bottom out intensity (watching slow motion YouTubes at 0.25X speed).

And in terms of bullet manufacturer quality, I have a Frankford impact hammer that enables nondestructive bullet disassembly. My experience thus far has shown Underwood to have by far the most intense and consistent disassembly forces, and powder fill depths have been imperceptible, bullet-to-bullet, a huge contrast to the other brands I've so far encountered. I trust Kevin Underwood's quality above all others, period.

So again, in sum, my happy situation is 15 rounds, completely concealed, with industry-best performance (with minimal short barrel penalty) and no additional risk of frame damage. The only downside is you can no longer impress the ladies with how easily it racks. Once they feel the buttery smooth trigger, however, it's game over.

http://www.czforum.com/forum/index.php?topic=4798.msg20513#msg20513

http://www.czforum.com/forum/index.php?topic=5463.msg23034#msg23034

[PappaWheelie]

Since there is no SAAMI spec, you have no idea what a manufacturer really means when they call something +P+. Only 4 cartridges have an actually defined +P rating (.38 Special, .38 Super, 9x19 mm and .45 ACP).

The manufacturers can very easily say you voided the warranty by firing +P+ ammo.

Good points, eastman; thanks for raising them!

Re. the factory Warranty, I wrenched on CZ and Jawa motorcycles in my youth and observed an "overbuilt" quality to them.

Having seen the same in my CZ 2075 RAMI BD, I concluded that CZ pistol robustness, like Jawa-CZ motorcycle robustness, needs no "Warranty," against design frailty: the parts are designed to be "bulletproof" by simple observation, and that against NATO 9mm pressures, which we designate +P+, and so are themselves the best warranty. I came to this conclusion before undertaking my first trigger job, which technically also voided the warranty.

http://www.czforum.com/forum/index.php?topic=4798.msg20513#msg20513

What I've learned in the interim far outweighs preservation of the ability to send into CZ-USA for whatever. And no, I'm not advocating the use of +P+ ammo (especially from lower-quality suppliers) without an accompanying change of recoil spring to balance the pressure increase as your comment seems to imply.

http://www.czfirearms.us/index.php?topic=93273.msg711859#msg711859

https://www.realguns.com/articles/276.htm// "...Tough Neighborhood Europe..."

Re. not knowing what pressures are represented by +P+, I trust the observed quality of Kevin Underwood's production, and his obvious (to me, at any rate) industry cutting-edge status for round-to-round consistency in this regard. What I've seen disassembling production bullets with my Frankford Arsenal impact hammer puts him in a class by himself.

[ZanderMan]

I used to on a CZ Jawa. Wish I?d held onto it.

[GBUS]

Hey Pappawheelie, thanks for the insight on your bullet testing and the Rami in general as I'm new to this gun as you know.

I've read a few threads on the Rami recoil spring failures and as a precaution ordered three of the assemblies when it was mentioned that they were back in stock at CZUSA.
That should tide me over for awhile and I'll hope one of the major players comes up with some quality replacement springs.

I haven't shot anything but 124gr Speer Lawman range ammo in the gun so far, but once I've gotten 500 rounds through it I'll probably start running some of what I have available in SD ammo for function testing.
What I have on hand is Hornady's Critical Defense 125gr and the 135gr +P Critical Duty.
Hornady 125gr XTP and then Federal HST 124gr and some older Federal +p+ duty ammo I just pulled out of one of my ammo lockers.

Cheers,
GB

[MeatAxe]

Right, Pappawheelie! I also have the DPM springs on my 97BD. I rotate the Rami DPM aprings between my 9mm and .357 Sig Rami.

Interesting...

Who did your conversion to .357 SIG?

Did you start with a 9mm or a .40 S&W Rami?

[dannyvi]

I have a .40 Rami and purchased a 9mm barrel. I'm trying to remember yhe guy on the 1911 Forums who did the conversion. I think all that was needed was machining the throat ro fit the larger .40 case. The .357 feeds better than the .40. Been having the .40 nosediving sometimes.. i do blame it on the mag.actually did this 4-5 years ago. CZ Custom ,I think, dos this to the compact CZs. . I do use the .357 in my rotation. I have the DPM recoil assembly on this also.Works just as well with the regular CZ springs though. Very flat shooting  and  feels like kicks leas than a .40. Just my opinion.

[MeatAxe]

I have a .40 Rami and purchased a 9mm barrel. I'm trying to remember yhe guy on the 1911 Forums who did the conversion. I think all that was needed was machining the throat ro fit the larger .40 case. The .357 feeds better than the .40. Been having the .40 nosediving sometimes.. i do blame it on the mag.actually did this 4-5 years ago. CZ Custom ,I think, dos this to the compact CZs. . I do use the .357 in my rotation. I have the DPM recoil assembly on this also.Works just as well with the regular CZ springs though. Very flat shooting  and  feels like kicks leas than a .40. Just my opinion.

I hope to get around to converting a Rami and/or P-01 / P-06 to .357 SIG some time soon, which to me doesn't recoil that much more than a 9mm +P.

[MeatAxe]

https://www.youtube.com/watch?v=JULgWoLJGmQ&feature=youtu.be


Pappawheelie, you might try shooting your defense loads into a big pork shoulder / butt to see what they do in actual tissue and bone.

Shooting center mass or head shots when the SHTF, you stand at least a 50/50 chance of hitting bone before hitting vital organs. Unfortunately, a lot of 9mm HP loads (i.e. with light bullets) have a reputation of ricocheting off of bone (and not expanding properly) rather than smashing through en route to the vitals. That's why water jugs and even ballistics gel (unless it has actual bone or Synbone in it) isn't the most accurate test medium as far as "stopping power."