Special Weapons SP-10

Special Weapons SP-10

This is my Special Weapons SP-10. It's a unique American made piece that is based on the HK's delayed roller lock system. I've heard of these SP-10's being referred to plastic MP5's. That's not too far from the truth, actually. Internally, they are very much parts compatible with the MP5. The major changes are rather obvious. The receiver is made of a polymer that is reinforced with steel. The stock comes off with pins just like an MP5K end cap, but is not compatible with any of those stocks. The trigger housing is also MP5K type. Otherwise everything else is MP5 — the barrels are the same, the bolts are the same, the bolt carriers are the same, etc. I had a few reasons to want one:

  • looks cool (reminiscent of a UMP)
  • uses the relatively cheap 9x19mm round
  • American made (bigger deal to me than some might think)
  • based on the old, well tested, tuned, and understood HK delayed roller lock action
  • light weight
  • accepts registered HK sear packs
  • integrated picatinny rail
  • cheap (a similarly built MP5 clone would be 50% more expensive)

So, having bought it, what do I like about it? It’s quite easy to handle. It’s easy to clean. It’s pretty accurate (not that I’m a great shot to begin with). It’s comfortable. It’s quiet. In fact, it’s deceptively quiet. I even tried shooting it without hearing protection once. That was a mistake. The sonic crack from the round was still a bit uncomfortable.

From the beginning, Special Weapons announced that a folding stock would be available (it was originally announced before the AWB sunset). They also stated that a flashlight would be available for the integrated mount. Both were released after I purchased my SP-10 in May 2005 and I have since acquired them (folding stock is installed in the top picture, along with an ATM red dot). The folding stock is really what completes the rifle for me. The original fixed stock was mounted high enough vertically that it basically required me to put a red dot on it. I could just barely use the iron sights. The folding stock line is mounted maybe a half inch lower so that when it folds, it can latch under the catch on the shell deflector. That’s makes things right for me. I can just image how close to perfection it will be with the intended short barrel (about 8 inches as opposed to the 16 inch barrel on it now). I’ll start my Form 1 paperwork after the big move to Tennessee.

So, the bad news is that it didn’t run very well. Jamm-o-matic is the proper description. It’s been to Special Weapons three times to try and make it right. The first trip got the “standard” treatment — meaning replaced ejector and ejector spring. That seems to be the most common fix for people having problems, and it seems to work. For me, that made things better, but not right. On the second trip it was found that my ejector was installed 0.030 inches too low. After that, I thought everything was fine, because my next 500 rounds through it resulted in 99.2% success (which is supposed to be within spec reliability). The next 500 rounds after that weren’t so spectacular, a good 16 FTE’s. The next 300 rounds after that were totally abysmal with 25 FTE’s. Near the end of that session they were occurring every 2 or 3 rounds. It’s now back from the third trip. The invoice came back saying that they replaced the extractor, extractor spring, and bolt face. What it didn’t come back with is my magazine. Without that I couldn’t really use it. So, after contacting them again I eventually got a new magazine. That only took 3 weeks to get. With the new magazine in hand, I ran another 600 rounds through it. It was perfect up until about 350 rounds. At that point I had 2 consecutive mag loads that jammed on the last round. A third mag load at around 425 rounds had an FTE. Everything else was fine. So, that session had 99.5% success. I didn’t get to clean it after that. I then took it out for another run and put 600 more rounds through it. This time I had somewhere between 10 and 15 FTE’s. Afterward, I cleaned and it sure was dirty. It certainly did “okay” considering how dirty it was, but my AK’s and Makarovs could (and have) handled that much grime without missing a beat.

It has now been sold. In some ways I regret it. So, I eventually replaced it with its follow-on model, a Coharie Arms PXP-10.

Special Weapons SP-10