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5/30/2010 6:14:31 AM EDT
Ok, I'd like to build/buy a 9mm upper for my SBR. I'd like to be able to switch to 5.56 without too much effort. I read the 9mm FAQ but most of it seems way outdated. I'd like to buy the 5.5" barrel, ramped bolt and 9mm upper from Spikes. I'll be buying a hammer that I can use for 5.56 and 9mm. I'd like to know what mag block I would need to buy to allow be to use unmodified Uzi or Sten mags? Or if there's a mag block that would let me use the 33rd Glock magazines.
5/30/2010 6:32:17 AM EDT
[#1]
VM-hitech block allows you to use uzi mags.
Unfortunately, quality has gone to crap here lately. I just got one a week or so ago and It won't lock into one lower and won't fit into the mag well of another lower. Finish looks like spray paint and was chipped before I got it out of the bag.
5/30/2010 8:00:02 AM EDT
[#2]
I just bought one of the Spikes blocks and it has worked 100%. I had made the mistake of picking up one of the C-Prod blocks when I bought my 5.5" upper. My RRA upper came with a ramped Colt bolt and I use Colt mags. Installing/removing the block takes less than a minute. I bought one of the Spikes 9mm buffers too, but it has worked great with the H3 buffer I normally use.

Andrew
5/30/2010 9:01:11 AM EDT
[#3]
Do the Spikes blocks require the use of their mags or other modified magazines? I don't mind spending $30 for a quality mag, but I don't want to be paying $50 per mag.
5/30/2010 9:42:27 AM EDT
[#4]
Quoted:
Do the Spikes blocks require the use of their mags or other modified magazines? I don't mind spending $30 for a quality mag, but I don't want to be paying $50 per mag.

Spikes' blocks, like Rock River blocks, require a Metalform/Colt/CProducts magazine, but also like with the RRA block, the combination of these magazines and blocks provide for a bolt hold open function.  I would stay away from ProMags because they don't seem to be robust enough to retain a full load without bulging.  You can sometimes find Metalform mags for around $30-I just got a couple from CDNN for that price-but you have to keep your eyes peeled.  CProducts magazines list for from $15-$18, but it's a good idea to insist on the latest version, no matter whom you get them from.

My next block will be a Spikes' block.  My current/only one is from Rock River.  I have had good experience with CProducts magazines-do not let chatter here make you think that ALL CProducts 9mm magazines-or more accurately all equipment combinations used with CProducts magazines-are faulty.  But do note that unless you take a few steps, you can have some very frustrating problems with any bottom-load block and CProducts mags; these magazines are not "identical" to the industry standard Metalform magazines by any stretch, as they have a very different feed lip geometry and follower.  However it is possible, even pretty easy, to adjust the block so that it will handle most magazines without a glitch.

My advice if you go with one of these magazine blocks is to spend a few bucks and get a number of different magazines from different makers.  Try them all and see if you have any problems that a little adjustment of the block's height doesn't clear up.  Some guns just do not like some magazines or magazine+block combinations, and trying a few different kinds of magazines with a new block will help you figure out what your gun does and doesn't like quickly and at a minimum expense.
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