Couple of AR Questions???

[Guest GLOCK2340]

I am thinking of getting a S&W mp15 upper in 5.45 x 39mm because of ammo costs. I would like any opinions or experience with this caliber on the AR platform. Can I use the 556 mags? Will the Bushmaster gas piston conversion work on one of these? Is worth doing or should I stick to 5.56? I look forward to all of your comments!

[Magiccarpetrides]

if your even faintly considering this buy up ammo now while its still cheap :-D

[TGO David]

Can I use the 556 mags?

Yes but reportedly some brands of mags work better than others. The S&W guns are shipping with C-Products mags from what I understand.

Will the Bushmaster gas piston conversion work on one of these?

I believe that the bolt carrier is different with the 5.45 upper. A gas piston conversion includes a new bolt carrier since it is no longer a direct impingement system. Therefore I am lead to believe that you would need a gas piston conversion designed strictly for the 5.45mm round, or at least the carrier designed for it.

Is worth doing or should I stick to 5.56? I look forward to all of your comments!

Whether it is worth it or not depends on what your priorities and requirements are. For cheap shooting the closely approximates the "feel" of shooting 5.56 this is the hot thing going right now. But it's not the same as shooting a 5.56 round.

If I were you, I'd check over on www.m4carbine.net and read some of the threads about the 5.45 conversions. There are several and all easily found by searching. Definitely search first before asking something that may have already been addressed. They tend to favor people who follow the old saw that God helps those who help themselves.

[Magiccarpetrides]

Thanks for the link tungsten...im still up in arms between this and a Tantal.

[Guest GLOCK2340]

Thanks for the comments guys. I saw on AIM some mags specifically designed for 5.45, but had read in some places that you could use the 5.56 mags. Do you guys know of anyone that makes a gas piston 5.45 or a conversoin kit? Thanks for the comments, I am going to search the link Tungsten gave me now.

[TGO David]

Apparently my suspicions were correct as there is some discussion in this thread on M4C regarding the possibility of a gas piston upper for 5.45mm