Installing a M1S LPK into RRA lower.  After putting bolt release spring & plunger into hole (not really forcing it mind you), it is now stuck with no tension for the bolt release to operate.  I am not able to get the spring and plunger back out.  If I am not able to come up with a solution to getting it back out, I am going to be forced to take it to a gunsmith.  This is probably going to pretty much negate any savings I expected by building the rifle myself.  In the future I will without a doubt use a name brand LPK.  Any suggestions?

I just built an OLY lower with M1 Sales parts kit yesterday. It went smoothly...learned a few things. Is the nut still on the shaft of the plunger? Will it turn? If the nut is on the threaded shaft and won't turn, it must be cross threaded. Did you depress the mag catch button far enough in, to give clearance to spin the catch over the bumps on the other side of the reciever?  Let's try to come up with a solution so you can smile and be happyhelp                                                     PyroMate

Re-read the post.  You are talking about the magazine catch - I am talking about the bolt release.  I already have the mag catch installed.

Sorry about that. Kids were crawling all over me as I read it the first time. he                                                Pyromate

had the same problem with a M1S kit, I used a small dab of  hot melt glue and a wood match stick, the plunger wasn't jammed in to tight but enough it wouldn't fall back out , if it is in there tight  you may have to drill and tap it out, also had to drill out the pin hole in the bolt latch so it would work.

I checked for crap inside the recess before I installed it.  I live in an apartment so I don't have an air compressor or a buddy with one.  Just by looking at it, I won't be able to put a dental pick in there as there is almost no lateral play.  When I push in on it, it will push in and spring back up but not far enough to grab with needle nose pliers.  Magnet doesn't work either.  Shit.  I thought I was going to be able to zero this weekend.  Yeah right.  There is no way in hell I'm going to be drilling and tapping it myself.  

I was thinking..on this.. Maybe you could insert a proper size drill bit on top of the parts... push in lightly and twist the bit slightly to remove the burr that is keeping the parts from springing loose.  I suppose it would worth a try. hinking.gif

I installed a M1S LPK in a OLY maxhard lower a couple weekends ago and experienced exactly the same problem.  I kicked myself hard because I didn't have the right size drill bits to clean out the holes in the lower and proceeded anyway.

When I placed the spring and plunger in the hole, the plunger was immediately stuck.  I didn't know what to do and pushed it in further thinking that it might clear the obstruction.   I couldn't think of how to get it out, without drilling it out.  So, I decided to proceed more carefully with the remainder of the build and deal with the plunger later.  However, I did put a couple drops of oil in the hole on top of the plunger.

When it became evident that the pivot pin detent hole was obstructed, I went to the hardware store and purchased a new hard metal drill bit of the correct size and drilled out the hole (there was a significant obstruction that I drilled through).  Everything went very smoothly from there.

Somewhere in the middle of the process, after I came back from the hardware store, I noticed that the plunger had sprung free and was placing tension on the bolt catch release.  The bolt catch release has seemed to work since, but I've been concerned that it may not be moving freely.

After reading your post this evening, I took the bolt catch release pin back out and inspected the plunger, spring and hole closely.  The hole appears to be very smooth and free of any burs, and the spring and plunger seem to move freely.  Frankly, I can't see why the plunger got stuck in the first place.  

I must admit, after reading a number of posts regarding M1S LPK problems, and especially the problems with the bolt catch release, I'm a little aprehensive about the bolt catch release.  I'll be firing the rilfe soon, so we'll see.

Good luck!  I hope it frees up for you.

It's probably just out of spec:

The M1 LPK that came with my upper,  both  the hammer and disconnector were WAY out of spec, and hung up when the rifle cycled. I had to push the trigger forward with my finger to get the DC to let go of the J hook on the back of the hammer after each shot.

 Comparing it to a RRA LPK, it was obvious that the disconnector was basically way out of spec, cheap import pot-metal junk. Replaced Hammer and Dc with RRA, and the rifle now functions 100%.

No more LPK from M1 for me.

Good Luck!

SG

Just a question not a flame to anyone I'm new to building my own ar just finished my first lower from dpms everything went smooth except pivot pin detent took me 4 hrs to find it. The only other lower I ever put together was 16 years ago.
But if M1 parts kits/lots of other problems with their stuff is so bad is the savings really worth the hassle.  I price checked everything pretty good before building my rifle just didn't seem like the savings was worth the risk.

austinrgr375, Take some superglue and glue a wooden match or large toothpick or similar item to the end of the plunger and pull it out. Take a knife and wittle it off if necessary(the removal tool). Clean
all the holes on all receivers before you assemble them. Nothing wrong with Model 1 parts. I've built more than 5 rifles from their parts and never had a problem that I did'nt cause.
When you put the detent  in the pivot pin, do it in a clear plastic bag so you catch it if it springs out.
Good Luck! Let us know how you make out.

I built several kits from M1S also with no problems, but with this last kit the lpk sucked, I had to fit and fiddle with almost all the parts to get them to work, I'm thinking that with all the demand for kits and parts, M1S is sending out 2nds or maybe changed their suppliers or both, whatever has happened the lpks are not of the same quality as in previous kits I've built.

I had a similar problem with an Oly plinker(no jokes) Required me to drill it out..trust me it was a touchy area to be drilling a detent out in the first place but given the plinker has a cast upper and lower it was even more touchy..but i lived and so did the plinker.Fun rifle for the price and i can shoulder bump it better than any other AR ive tried

I'm going to the grocery store and will pick up some super glue and give it a try.  Half of the folks here say the LPKs for M1S are shit and half say they are just fine.  I wish we had a database  set up documenting problems people have had and solutions they found for them (I'm not nerd enough to do it).  The upper receiver, bolt, barrel and even the furniture that I got in the M1S kit look to be as good a quality as any Colt I was ever issued in the military.  I really have reservations about the LPK though.  I talked with a gunsmith and he said he'd install the bolt catch for free and would only charge me for the part if he had to replace it.

Anyways, thanks to everyone for the suggestions.  This is my first build and this problem has definitely taken some of the fun out of it.  Oh well, live and learn.  I still look forward to getting some rounds through this thing.

The LPK I have from M1S was out of spec, you couldn't even get the selector switch into the reciever. Total Junk.

Both LPKs I got from M1S required widening the hole in the bolt catch for it to function correctly with USGI mags.  They were installed on an Eagle Arms and DPMS lower. The LPK's hammer and trigger pins and safety selector are too wide for the DPMS and will stick out a little. I will probably be replacing it with Bushy parts.

As for the M1S barrel, I was getting a 3 inch grouping at 50 yards with iron sights.

I installed my M1S LPK on an Ameetec lower last week. I as well had to file out the bolt catch hole because the role pin fit it too tight. I also had to cut a little off the front detent spring. Other than that everything went together fine. I've been building AK's for that last 6 months, so these two issues were easily dealt with.

I'm coming to this thread late but I wanted to ask while all these experienced builders are reading.  I am starting to put the parts together for my first ar build.  I would like to know the proper drill sizes I might need if the holes need reworking.   I'll be using stag stripped lowers and m1 kit uppers.

My M1S LPK in my 19 post ban kit I built a while back kit was junk.  My FCG wouldn't fit together at all because it was flat out not in spec.  Everything else has been fine though, through 2 different upper receivers and mucho taking apart and reconfiguring

Well, the RRA LPK went right in my Ameetec lower. No problems at all, everything fit perfect. Even the roll pins went in smoothly. I decided not to use one of the parts kit LPK's which in turn made me decide to even use a cheaper kit at all. I went with RRA parts and I'm geting a CMMG upper. These higher quality parts aren't that much more than Model 1 or M&A or whoever.

Model 1 Sales lower parts kit strikes again. Mine had three (3) defective parts - selector, pivot pin, and bolt catch.

Still having a problem? Let me know in Ausitn.

I had this same problem with a mod1 kit I put in a Busy lower...   I've since bought one other mod1 kit that went together fine after I sanded the crap out of the plunger (in a AMEETEC), and a RRA that went together slick (without modification) in an AMEETEC...

But more to the point, I posted here asking for help, and got a lot of suggestions...  from using petrating oil (whick I tried), to a solder iron to use heat and the dissimilar groth of the alluminum lower and the alloy plunger, to hot water for the same, to superglue...

What I did was:

1 took a drill bit put a small dimple the center of the plunger,  then carefully with a smaller drill bit (1/16) I drilled a hole in the plunger using the dimple as a starting guide

I then put a 1/16 punch in the hole I made and twisted and pulled and the plunger came out.

I then sanded the crap out of the MOD1 oversized/non spec plunger and took a pair of needle nose vise grips and tested it for fit so that I wouldn't run into that problem again.   I do this on every build now... the testing part, then if needed I sand...  though I think its silly to have to, so from now on I'm gonna only use RRA which seemed to be a much higher quality kit.

I used a RRA LPK in an Ameetec lower and the two seemed made for each other, no problems at all and everything feels perfect. I was suprised that it was so easy considering that it was my first build. I see no reason to ever use anything but RRA parts based off of this experience.

The biggest problem with using Model 1 is that if you have to buy a LPK from someone else that actually works then it starts to negate the cost savings of the kit, that's why I abandoned the idea of using Model 1 all together.

Austinwft: I really haven't tried working on it other than the match stick adn superglue suggestion (didn't work by the way).  It's getting really close to Christmas and I don't think I'm going to do anything until afterwards.  I'm not really set up well enough in my apartment to be drilling this thing out.  If I get a gunsmith to do it, it's probably going to cost more than I'm willing to spend before the holidays.  Even if I did get it out myself, I'm going to want to use a quality LPK to finish it out (another $55).  Honestly the only easy part for me was the magazine release.  Hey kids - don't use cheap LPK's  (especiall for your first build)- you'll thank yourself later.

Quoted: Austinwft: I really haven't tried working on it other than the match stick adn superglue suggestion (didn't work by the way).  It's getting really close to Christmas and I don't think I'm going to do anything until afterwards.  I'm not really set up well enough in my apartment to be drilling this thing out.  If I get a gunsmith to do it, it's probably going to cost more than I'm willing to spend before the holidays.  Even if I did get it out myself, I'm going to want to use a quality LPK to finish it out (another $55).  Honestly the only easy part for me was the magazine release.  Hey kids - don't use cheap LPK's  (especiall for your first build)- you'll thank yourself later.

I'd bet there is a Gunsmith who'd do it for under $20...   its not that hard... (even I did it!)

As for a whole new LPK... give it some time... I think you'll cool enough to make the one you got work fine, just sand down the bad plunger, or better yet spen about $4 and get a new one and you'll be ready to rock.

For what it is worth, I have built many rifles using M1 parts.
0 Problems. Not one.
Two have been recently.
I am about to order two more kits and M1 will get my money once again.