Operating Slide Spring - attn: Gus Fisher
Gus and all,
Recent threads/posts indicated that a slide spring should be replaced when it's about 10", and a new one shoud be in the 11 to 11-3/8" range. My old one was 10-1/4 so I took a chance and ordered one through Numrich (yeah I hear the snickers). Well, not much $$, only $12 shipped.
Before it arrived I bought a spring kit, 8 new springs, for $20 from local gunsmith - duh, should'a gone there first. The slide spring in the kit was a proper 11-3/8. And he said these new ones are made from better steel than NOS wartime. Said spring will be tried out next week.
When the GPC spring arrived it was wrapped in what appeared to be original GI heavy paper, heavy grease (cosomoline?), looked like a long sticky greasy handrolled cigarette. It took 10 minutes to finally get it unsealed and opened. The spring measured just UNDER 10". HUH?
Well to my question - either Numrich re-greased and re-wrapped a used spring, a lot of trouble for 7 bucks, OR.....were new GI springs originally only 10"??....OR the gov't wrapped and surplussed used springs?? Opinions?
NOS USGI springs are 10 1/4 inches long.
Bet that new recoil spring is nowhere near the specified 121 coils either. Sounds like a Sarco spring kit where half of the springs are not close to carbine specs.
As a general rule, when someone tells you they have a part "better" than milspec, ask to see the test data. What your gunsmith really meant was that was what he had in stock.
I was first trained as a Marine Corps Armorer in 1972, but that was long after the Corps had quit using M1 Carbines. We still had M1 Garands, though primarily as NM rilfles and I learned to work the Garand from Armorers who had worked them both as standard Infantry Armorers and NM Armorers. I learned to work on Carbines a little in the early to mid 70's from older Marine and other Service Armorers, but did the most work on them after Garands and Carbines started coming back from Korea in the 1980's.
The reason I mention these things is that I was not around when Marine Armorers had determined the minimum allowable lengths for Carbine Springs as I was around for that for Garands, M14's, and .45 pistols - to name a few miilitary firearms. The minimum lengths of springs were NOT listed in G.I. Technical Manuals until beginning with the M16 rifles. However, military armorers through long experience had learned what the minimum length and condition of springs were to ensure the firearms would function properly. I have had copies of the blueprints for M14's, M1 Garands and M1911 pistols since the 70's. Blueprints for the Carbine were not really available nearly as widely as those and since we didn't use Carbines even for NM work, I never got a set for Carbines.
I have military Techinical Manuals on the Carbine and unless I missed something over the years, those manuals also do not list minimum lengths of Carbine springs. Standard Military Armorers of my day and before were only concerned about the minimum length and condition of springs and not what the Blueprint Specs were for them. Heck, I doubt most Military Armorers could quote you the Blueprint Specs. I know I could not until I got copies of the blueprints as a NM Armorer.
So, when the Carbines started coming back from Korea in the 80's, I got with older Marine Armorers who HAD worked Carbines and they did not remember what the minimum length of the slide spring was, if they had even determned it as they had with Garands, M14's and .45 pistols. The length of G.I. springs that I quoted came from actually measruing the overall lengths of G.I. replacement springs over the years. The minimum length I posted earlier has come from experience of measuring NOS or excellent condition G.I. Surplus Springs and seeing what minimum length was required to get Carbines to function correctly. Basically, the same thing that earlier generations of Military Armorers had done for years with other military firearms.
I STILL don't know the blue print specs for Carbine Slide Springs as I don't have a copy of the blueprints. Eric of Nicolaus Associates is currently working on getting the blueprints copied and offering them for sale. I do not know when they will be ready, but I'm going to get a set when he has them.
Gus, Thank you for your comments, it certainly has a "been there" significance. I think what you're saying is experience can be a good, if not the best teacher. At this point I'm wondering if there might have been a difference in the M1 vs. M2 spring length.
So I have what I assume are a new 10" spring and new 11-3/8" spring. I guess I'll just try them and see what works best. Will advise what teacher says.
See Kuhnhausen for the performance test for springs involvolving loading the spring outside of the carbine.
If your longer spring has 114 coils, it's a high speed spring from Sarco. You don't even need to count the coils - it's obvious when held next to the USGI version. Also, it lacks tapered ends. High speed springs often cause failure to feed issues, particularly with lower velocity ammo like Aguila. The compressed length of the Sarco spring is such that you might need more than your fingers to compress it enough to install it. The "good news" about the Sarco spring kits is that the hammer and trigger springs appear to be USGI.
Well from your descriptions I do indeed have a Sarco high speed spring, 114 coils, more tension than the shorter 122 coil 10" replacement from Numrich. I'll slip that one in, it should be OK as some of the ammo I have been shooting is in the non-GI Aguila category.
I very much appreciate all of your help in sorting this out. lee
There is no difference in the recoil springs on the M1 and the M2. Same spring for both right from the start.
I used the Wolf springs in alot of carbines and they worked very good. Instead of just buyng the OP spring its cheaper o buy the whole spring kit for everything.
Ditto on the Wolf springs. Even though Wolf's penchant for increasing tension by 10% gets panned on M1 and M1 Carbine discussion groups, I have used their kits in both weapons with great results. I particularly have found that new M1 Carbine 15 rd. springs from Wolfe cure a lot of feeding issues.
Warning: Amateur gunsmith, your mileage may vary, keep your powder dry