Looking at an SP1 MG locally.. Any downsides?

[taymag]

Its in good condition and the only negatives I've read are no fencing (which is kind of weird but not a game changer) and the front pin right?

With the front pin adapter (I know there are permanent fixes too) why is the front pin even a problem? I can see it as a MINOR inconvenience, but not something that would make someone not want to buy one.

Anything I am missing?

Also, the conversion was done by Northwest Arms, any good/bad info on them over the years?

 

[rentprop1]

no fencing was correct on those, its called a slab side

 

[sniperdoc]

The original M16 was a slab side. The fencing was added to later modifications.

 

[Hey...]

The only downside is if the price was too high for the current market.

How much?

 

[taymag]

The only downside is if the price was too high for the current market.

How much?

I don't like posting "should I buy this or that" with price (it will be 18 after taxes, excellent condition and piece of mind of seeing it and test firing it before hand are worth it) because then everyone automatically goes to "that's too much blah blah blah" or "that's a deal! Buy it!" when I really just want to know the ups and downs of the SP1 compared to the other options / reweld converts / etc.

 

[Hey...]

Already said my opinion about your question and was curious about the price hence my asking.

Would love to own that SP1 myself.

 

[100 bullets]

SP1 disadvantages
The slab side, no fencing, fencing was installed to prevent accidental mag release and the fencing helps prevent that. Dropping the mag while handling the gun in combat is bad. If you're just target shooting and not doing competitions really shouldn't matter. Remember you keep your finger off the trigger until you plan to shoot, when your trigger finger is extended forward what is it near?

Large pin versus small pin, the SP1 uses large pin uppers, they are hard to get new uppers and flat top uppers are difficult to find and are special order. The inserts are not the perfect solution you can still have play problems. Personality I would pay the have the lower converted to take small pins uppers. What ever you pay for your gun calculate that cost into the price you're paying and decide if it's still a good value. Remember you can send the gun to be converted while you're waiting for your form 4 to come in. I'd find out who you want to do conversion and cost beforehand.

Sorry I don't know anything about Northwest Arms conversions.

 

[ccosby]

Can't speak for who did the conversion myself. Biggest issue is you will need an adapter to run other uppers unless it has had a small pin conversion done. My understanding is that colt didn't do the stupid larger trigger pins until the 90's so that should be fine.

My concerns would be the engraving for the conversion and if the sear pin holes is in the right location and aligned correctly. The engraving just because I've seen some really ugly jobs done and the sear pin holes as I've seen a few be off.

For the money though it sounds like a good deal. Sure you have to deal with a front pin adapter but at 18's it is in line with some of the cheapest registered receivers and I'd rather have the sp1 instead of a cast receiver and the sp1 is going to have a higher chance of not being out of spec vs lowers Olympic made(although they can be fixed).

Edit: Daniel Defense was making a flat top upper for the sp1s with m4 feed ramps. If you don't care about swapping uppers much that might be the way to go.

 

[sniperdoc]

The "slab side" could be seen as a bonus if you want the look of an early M16; add an upper without Forward Assist, Triangle Handguards, Pencil Barrel,& non-removable Carry Handle w/A1 sight); Grip should be old type without finger groove, and an early style stock.
Of course, the Fire Controls should be Safe,Semi,Auto

 

[Vegas SMG]

18k all in sounds like the correct pricing of a Colt SP-1 conversion. Condition and discrete manufacturers makrkings add to the price. It'll make a great shooter, and like most guys, I'm a shooter, not a collector.

At $2.50 a set, pick up several of the off set pins and call it good. People cite the time to swap uppers as a deal buster, but how many guys actually swap uppers at the range and how many uppers are swapped each time out? It takes an extra 30 seconds. Seriously. As you correctly noted, it's a minor inconvenience, hardly a deal buster.
http://www.jsesurplus.com/coltreceiveroffsetadapterpin.aspx

Moedern lowers have full fencing. As a hobbiest shooter, I'll bet you'll never accidentally drop a single magazine due to the lack of a fence. Guns such as the FN FNC also lack a mag release fence, and I've never heard anyone complain about dropping a mag accidently. I know I've never dropped one on an SP-1 or FNC, so I t's a non issue other than aesthetics.

The sear pin axis hole alignment is probably the most critical area to be concerned about. Take a close look and make sure it was drilled straight across. Inspect the sear itself to make certain there's no material removed or added to compensate for a misalignment of the sear pin holes. Also look at the front take down pin hole to make sure it's free from any cracks or egging. The SP-1 hole has less material around the hole and I've seen a photo of one that was damaged. The SP-1 shares the same fire control group component axis holes as the standard M-16, so there's no concern there, but a quick check for egging or wear on the hammer axis holes is a good idea. Blowback upper use like 9mm can cause accelerated wear in this area.

Best of luck in your decesion!

 

[taymag]

Awesome.. Thanks for the info, I feel slightly better about my inspection checklist now hah, ill probably go take a look at it this week

 

[rparsons3]

I bought one last year for cheap (12,500) wasn't looking for one but could not turn that down, I have an M16A1 so now it just sits in safe and I shoot the crap out of the SP1. mine runs great has never stopped, I replaced all internals, probably wasn't totally necessary but they were original ones from early 80s so I replaced them. (I bought the gun from the original owner) I left the front large pin hole alone, there is a model of colt upper that are A2 style with the large front hole and have m4 ramps also, I bought 3 off of gunchoker and built my different uppers with different length of barrels. I was going to convert the SP1 to small hole but I absolutely hate to ship machine guns, so I just decided to get some different large pin uppers for it. I also had one C7 A1 style upper that has shell deflector (I am lefty so I need deflector) and had a local shop drill out the front hole on it to fit the SP1, fits fine.

I never before used steel 223, but now I buy Wolf steel and shoot the snot out if the SP1 with wolf steel, barrels are cheap and I can replace it myself if needed. So, I really like mine and the front large pin hole can be dealt with in different ways as stated above. If you like the price go for it and enjoy!!!!

Also KNS makes a large one piece front pin for the SP1 so you don't have to have a screwdriver to take it down.

 

[taymag]

I bought one last year for cheap (12,500) wasn't looking for one but could not turn that down, I have an M16A1 so now it just sits in safe and I shoot the crap out of the SP1. mine runs great has never stopped, I replaced all internals, probably wasn't totally necessary but they were original ones from early 80s so I replaced them. (I bought the gun from the original owner) I left the front large pin hole alone, there is a model of colt upper that are A2 style with the large front hole and have m4 ramps also, I bought 3 off of gunchoker and built my different uppers with different length of barrels. I was going to convert the SP1 to small hole but I absolutely hate to ship machine guns, so I just decided to get some different large pin uppers for it. I also had one C7 A1 style upper that has shell deflector (I am lefty so I need deflector) and had a local shop drill out the front hole on it to fit the SP1, fits fine.

I never before used steel 223, but now I buy Wolf steel and shoot the snot out if the SP1 with wolf steel, barrels are cheap and I can replace it myself if needed. So, I really like mine and the front large pin hole can be dealt with in different ways as stated above. If you like the price go for it and enjoy!!!!

Also KNS makes a large one piece front pin for the SP1 so you don't have to have a screwdriver to take it down.

Why the m4 ramps? And I cant just buy a SP1 receiver because it doesn't have sear relief right? So why were other A2 uppers even made?

 

[rparsons3]

It is my understanding that M4 ramps were started when the military went to 62 gr ammo in carbine length gas systems, I'm far from an expert but I have read this in many articles. I have also read that the ramps aren't necessary, I just put together an upper for mine using an SP1 upper with no ramps and will test it this week, it has a mid length gas system. You are right SP1 uppers don't have sear relief cuts, but it takes my local gunsmith/machine shop bout 5 minutes to cut the relief in a SP1 upper, touch it up with burchwood casey aluma black and good to go. I'm an older guy and have read many articles and such on colt ars and M16s, Colt made many many variations of each and I still learn things I did not know. Apparently the colt RO727 model m16 has just the upper style that I want, A2 style, large front hole and has feed ramps, they show up occasionally on gunchoker. Most shorter barrels ar uppers that are sold now days have M4 ramps, I just try to match things ups for less potential problems, but have been told that uppers WITHOUT the cuts will work fine with barrels that DO have M4 cuts, but not visa versa, that is what the above mentioned upper I just put together has. My favorite combo for the SP1 I have is to leave the A1 stock on it and run it with a 14.5 or 16 in heavy barreled upper, I like the way the A1 stock fits me and it runs smoother to me with the mid length gas sytem than it did when I sat it up like a M4 carbine. Just my opinions, your mileage will vary you know............... (but I do sometimes throw on the 10.5 in upper to make it a flame thrower for the new folks)

 

[nklf]

I have an SP1 and it runs great. I use smal pin uppers with the offset pin. I installed the pin incorrectly once and it broke at the range. I keep a spare offset pin in the spare parts kit now.

 

[taymag]

Are there any issues with 10.5 uppers (suppressed or unsuppressed) when going full-auto or is it a "if it runs semi-auto" I likely can run the same upper/buffer auto?

 

[sleepy]

I run a 10.5" palmetto state armory cold hammer forged barrel upper on my A1 stock and gas system and it runs flawlessly. It does seem overgassed suppressed, so I don't run a can on it.

 

[rparsons3]

Are there any issues with 10.5 uppers (suppressed or unsuppressed) when going full-auto or is it a "if it runs semi-auto" I likely can run the same upper/buffer auto?

I have 10.5, 11.5, 14.5, 16 and rifle length uppers for mine, all run fine with a1 stock or carbine set up, I run the heaviest buffer that the gun will function with and hold bolt open on last shot when in carbine setup, I have found that regular H buffers work fine in my gun in carbine mode, with rifle setup i am not aware of different buffer weights, I do not own a suppresser for it, I think machine guns should be loud and obnixous ☺

 

[taymag]

Bought the SP1 today :twoguns.. I am going to have the small pin bushings put in while I wait

My question is... should I have M60joe look it over while its there even though its not a reweld and its in great shape? His words.. "It will cost $90 to look over the receiver and list the results to you"

Thanks for the help

 

[rparsons3]

Glad you bought it, (I am a big Colt Fanboy) I have never heard of a SP1 being out of spec and you said it appeared in good shape, so I probably would not spend the extra for him to check it, if it was another brand I could see it, BUT for complete peace of mind 90 bux is not much compared to the price of the gun, the one I bought had been shot probably a moderate amount and as I said it runs fine, no holes out of round or such. It ran fine with the original parts when I got it, but I bought a colt M16 lower parts kit on gunchoker, they are still listed if you are interested. The only thing I found on mine that obviously needed replacing was the gas rings in the bolt. Another reason that I chose to just use the big front hole and other SP1 or A2 uppers is that the colors match, my experience is that newer uppers will be noticeable darker than the sp1 lower....congrats and I hope these damn wait times start down soon. To answer your original question, there is really no down side to owning a converted AR, especially a colt.......except the ammo bill.....