ok guys I'm looking into putting a 9mm Oly upper on my pre ban Oly .223 lower.  if i put the socom block in how does it attach in the mag well? mag catch?  I do not want to have to make any permanent mods to the mag well since it is a pre ban and i don't want to muck it up.  sorry if this is a stupid question but i need to know how to use the cheep un-modifid $4 sten mags from tapco and i don't want to muck up my lower.I cant pay the $65ea oly wants for their mod-mags. so if i have to make mods i will just buy the whole rifle from oly.
TIA

socom block secures with the standard AR mag release with no modifications.

You'll need to scrunch down the overinsertion lips on the sten mags, or the mag either won't seat, or will ding the hell out of the bottom of your mag well from the contact.

I've used the socom block on with a Colt postban lower and, like Circuits said, it can ding the inside of the magwell a bit, but IMHO the damage is superficial and cosmetic.  In other words, I wouldn't beat up or file down my sten mags just to keep this from happening. In my experience they'll seat just fine.  

Gunbert,

I've got to disagree based on experience.  I've test fitted and fired over 200 different sten mags in AR-15/9's and M16/9's of various make and manufacture over the past few years.  Some fit fine and don't ding.  Some fit, but will scratch and groove the bottom of the magwell.  Some won't fit at all unless the overinsertion lips are squeezed down some, as with a vice or big channel lock pliers.

Some won't fit or function at all without more extensive alterations.

Really? I can't say I've had the same issues.

I don't have any experience outside of the one Oly conversion that I have used on two different lowers, a Colt and now a CavArms. I have 30+ sten mags that I tested for fit before I sent them to be refinished, and all worked fine. I even took the upper off, inserted the mag and socom block to make sure that everything fit correctly and didn't bind.

Could this be because of different mag well shapes from different manufacturers?  Were any particular company's lowers more prone to this than others?  I just want to know so I don't go giving out bad or incorrect advise.

I noticed that the overinsertion lips did mar the mag well on either side, but aside from a small wear mark and ding on the bevel there's no damage.  That was the Colt lower that has since been reverted back to .223, and all the USGI 30's that I've used since have functioned flawlessly, and all drop free.

thanks for the info guys.  One last question.  If the socom block is held in place with the mag release/catch how/what do you do to release the sten mag then.
Thanks again
Carl

Gunbert,

Cavarms has a pretty generous magwell lip, and works fine with most sten mags I've tried.

The sten mags which don't fit at all have a much smaller overinsertion lip than the ones you're probably used to - it's probably 1/3" instead of a good half-inch like the others.  The hood is also correspondingly smaller, and since the AR system uses the back lip of that 'hood', they lock in too low in the magwell to function.  You can make them work by pushing them into the magwell with your hand while firing, but that's no good except maybe as a range mag, and quite annoying.

To fix the sten mags with the short hoods, you'd have to weld or somehow build up a lower lip at the proper distance to engage the paddle release/catch on the socom style block.  They have the same problem in sten-converted macs, which also lock in on the bottom edge of the hood.

Quoted: thanks for the info guys.  One last question.  If the socom block is held in place with the mag release/catch how/what do you do to release the sten mag then. Thanks again Carl

The socom block has a lever underneath it that runs parallel to the mag. It catches on the back of the mag just below where the sten's regular mag catch would connect.  To remove the mag you simply grab the mag and the lever, squeeze, and yank out the mag.  It works pretty well, actually.

Thanks Gunbert.  Now I can't wait to order my upper, block and mags and go out shootin.  What 9mm ammo you guys using?  Is that Wolf stuff ok?  I guess I'll look in the ammo section too.

Thanks again
Carl

Oly will not warrantee your upper if you use Wolf ammo.  Load accordingly.

My Oly will run through Wolf ammo as well as anything else, however you might as well use that new winchester stuff you can find at walmart for $11 a box of 100, it's much better quality blasting ammo for not much more money.  And you don't have to pay shipping!

Quoted: ...however you might as well use that new winchester stuff you can find at walmart for $11 a box of 100, it's much better quality blasting ammo for not much more money...

Is this sold in every Wal-Mart? I have never seen this in any of the locations near me(South Alabama). Could anyone else elaborate further on the availability of this ammunition?

Quoted: Quoted: ...however you might as well use that new winchester stuff you can find at walmart for $11 a box of 100, it's much better quality blasting ammo for not much more money... Is this sold in every Wal-Mart? I have never seen this in any of the locations near me(South Alabama). Could anyone else elaborate further on the availability of this ammunition?

I just went and bought some more tonight.  Every walmart here in Las Vegas has the stuff, and now they have a 40 round value pack of 55grn FMJ .223 that sells for $7.47.  The white box 9mm runs $10.96 for 100 rounds.  And it's good stuff!

I hope they have it in your area, it's a very good deal on the 9mm.

Edited to add: Welcome to the board, Einrich!  

Quoted: Is this sold in every Wal-Mart? I have never seen this in any of the locations near me(South Alabama). Could anyone else elaborate further on the availability of this ammunition?

If you don't see it on the shelf then Wal-Mart will order it for you and start stocking it. All you have to do is ask? At least that's the way it works with my local Wal-Mart.

Just take a ball peen hammer and lightly tap the mag catch lips on the Sten mags flush with the rest of the mag body but no further.

Then, they will insert without a catch.

And the SOCOM block is the way to go with the Oly Arms PCR-9.  Can buy cheap used Sten mags from TAPCO for $25 for 10 with a bag to boot.

Please shot some decent ammo in there.

I use my reloads with ammo duplicating Golden Sabres and a lot of Federal Hydrashoks.

How about MFS from Hungary - AIMSurplus has good deals on it.  Or IMI ammo.  Or go to the Ammoman, good stuff there!

Just make sure it warm or hot.  The PCR-9 operates on blowback so slow stuff isn't what I'd recommend.  Want that bolt to work fast and freely.

I like to weld a 1/4" bar stock to the back of my sten mags . This stops you from over inserting the mag with the bolt locked back or the mag from raising up and hitting the bolt during firing.

Quoted: I like to weld a 1/4" bar stock to the back of my sten mags . This stops you from over inserting the mag with the bolt locked back or the mag from raising up and hitting the bolt during firing.

Do you have any pics?