Opinion on caliber conversions (5.7 and 5.45x39)

[Beryl]

With all of the silliness regarding ammo these days, I am becomeing more and more interested in other caliber alternatives instead of 5.56. I am particularly interested in 5.45x39 (a better round IMOHO) or 5.7, using the FN P90 magazines. Anyone have any experience with either of these? Who makes the best conversion kits? Can 5.45x39 be used in regular 5.56 magazines?

[[486]]

Originally posted by Beryl
5.45x39 (a better round IMOHO)

5.45 is a pretty good round, but it is optimized for steel core, it is cheaper but performs worse, even with fancy bullet designs. The 5.56 with the 55 grain lead core bullet will fragment, so long as you have a 16" barrel. This makes a huge wound channel, whereas the 5.45 will tumble, but won't come apart nearly as much, the biggest hole it can make is near the length of the bullet the long way, whereas the 5.56 will fragment and make a bunch of smaller holes that pretty much all tear together and make a big hole.

5.45 is cheaper, both to buy and to produce, but if your target isn't armored 55 grain .223 will do better.

[ftierson]

Smith & Wesson makes both a complete rifle (S&W M&P-15R) and a complete upper for the 5.45x39mm cartridge.

I have one of the rifles and a close friend has one of the complete uppers.

We're both quite happy with what we've got...

Forrest

[indy_Muaddib]

dont think ive seen a 5.45 AR mag yet thats worth a damn.

[Beryl]

While I agree with 486 in principle, I think it should be remembered that the 5.56 fragmentation is incidental, whereas all indications are that the military 5.45 is designed to tumble. While it does not necessarily fragment, it does begin its tumble almost upon impact, thereby creating a larger and longer wound channel. Of course, 62 grains of lead, copper, and steel exploding within one's torso has to be a real experience in itself You can't argue, however that 5.45 beats 5.56 pricewise hands down.

dont think ive seen a 5.45 AR mag yet thats worth a damn.

I have heard the same, but my question was more about whether or not 5.56 mags would work with 5.45. I have only seen reports on the mags made specifically for 5.45.

Any opinions on the 5.7 conversions using the P90 mags? 50 rounds is pretty cool, and I have shot an original full auto P90. It is a sweet weapon to shoot. I have heard various reports about the lethality of the 5.7 round, but I would think that in urban or jungle/woods it should work well. Ideas/thoughts?

BTW Indy, I like that quote.

[0007]

The 5.45 X 39 needs a different follower in to feed correctly from the standard AR mag.

[ftierson]

I use both green and black follower 30rd M16 mags in my S&W M&P-15R...

I haven't had any problems loading them to 25 rounds...

I'm not saying that's been everyone's experience, but it's been mine.

Forrest

[shortround]

I've used the C-Products 5.45 specific magazines and have yet to have a problem witha S&W upper. At $14 a piece they have been just fine.

[W.E.G.]

I ran out of storage space for third-tier stuff.

There HAS to be a limit where you just say "ENOUGH!!!"

No more oddball calibers for me.

[[486]]

Originally posted by Beryl
While I agree with 486 in principle, I think it should be remembered that the 5.56 fragmentation is incidental, whereas all indications are that the military 5.45 is designed to tumble. While it does not necessarily fragment, it does begin its tumble almost upon impact, thereby creating a larger and longer wound channel. Of course, 62 grains of lead, copper, and steel exploding within one's torso has to be a real experience in itself You can't argue, however that 5.45 beats 5.56 pricewise hands down.

The reason 5.45 is designed to tumble is it is steel core, and they are trying to make it into a good anti personnel round, the steel won't deform much if at all, so they have to design it it tumble to get as much energy transfer as possible, but a "incidentally" fragmenting bullet still does better in that respect than a bullet designed to tumble. You mention 62 grain, I was referring to the 55 grain load, the 62 grain one is lower velocity, so it has even less chance of fragmenting, especially in the shorter barrels everyone seems to like. Also, the 62 grain is steel core, and therefore won't be as good in an anti personnel application.

Guess I'm just sorta "venting" from all the people that think the .223 sucks, when it just evolved into it's suckyness.

[Rambozo]

I can't speak from experience, but I wouldn't put faith in the idea that the cartridge would feed from a standard magazine. But I do know that Cproducts has magazines, and I am happy enough with my Grendel mags from them.

As for the cartridge itself, it's one I have interest in aswell. But don't expect much in the way of reloading options. Comparing the standard loads, I would likely favor the 5.45. It seems apparent to me that there is a significantly higher ballistic coefficient, so you will likely see better external ballistics.

The 5.7, I regard as little more than a novelty. But on the plus side here, there is little problem in finding ammunition. Throughout the course of the "Obama Effect", it seems the little cartridge took no impact. A friend has zero problems getting the ammunition. But ballistically, I don't really think it's worth much more than shooting at soda cans.

Just my opinion.

[[486]]

Originally posted by Rambozo
I can't speak from experience, but I wouldn't put faith in the idea that the cartridge would feed from a standard magazine. But I do know that Cproducts has magazines, and I am happy enough with my Grendel mags from them.

Stimpsonjcat on this forum made the first AR in 5.45, standard mags are supposed to fit 24 or so rounds and feed fine, anti tilt followers are very bad if you will use 5.45 though, as the taper is different.

[gunsmoke]

Originally posted by shortround
I've used the C-Products 5.45 specific magazines and have yet to have a problem witha S&W upper. At $14 a piece they have been just fine.

I have no experience with 5.45, but I would like to 2nd the comment on C Products mags I've used their 5.56 7.62X39 and 6.5 Grendel and they all work flawlesssly, if I got a 5.45 I's get a doz C Product Mags and give them a try, their products that I have used have all been flawless, I would expect very good quality from them.

I wish they would make a MINI30 mag I've wanted one for a long time but finding reliable mags is a problem over 5 rounds.