JP polished springs are stronger than expected

[Disciple]

Tests by AddictedToComedy on Reddit show that the JP Ground & Polished action springs JPS-OSC and JPS-OSR are much stronger than mil-spec, at least when new, at about 13% and 19% above median respectively. These aren’t even marketed as extra-power springs though I have seen and repeated the figure +7%. Notably the JP rifle spring, as measured in an A5 configuration, is stronger than either the Super 42-rifle or Tubb AR10 spring.

In the A5 system the JP spring is only about 3% stronger than the Sprinco Green which seems to be popular there so perhaps it is not truly extreme. Nevertheless it’s eyeopening to realize that the JP Carbine spring in the A5 tube would actually be close to median mil-spec spring energy, if I’ve done the math right. (I calculate 34.1 inch-pounds.)

What are the consequences of being over-sprung to this degree, in either a carbine or A5 system?

[opngrnd]

I’ve thought about this and wondered if there aren’t advantages with 7.62 (and similar) AR10 designs. The mag spring, especially in 20 & 25 round mags, is pushing significantly more weight upwards, which would presumably lead to more difficulty getting the round out of the magazine into the chamber.

[markm]

Not sure of the consequences and I have no plans to find out. I’d never put an aftermarket spring in any of my carbines.

[Brahmzy]

Maybe I’m doing it wrong, but I’ve been running JP polished springs in all of my carbine & A5 guns for probably 12+ years. I cannot fathom the amount of rounds sent out of those rifles with 100% reliability.

I’m a HUGE fan of the JP Polished springs.

[Disciple]

@1168

I’ve experimented a good bit with springs, including on an intermediate gas system. What I have found is that increasing spring rate introduces stoppages to a functioning but lightly gassed gun. It also does not do as well as one might hope to tame a gassy beast. So there is little advantage, IMO.

I think that the optimal setup is a regular Colt spring, up to a Sprinco White or Hot White for Carbine buffers and Colt up to Tubbs SS for A5 or Rifle buffers. And tune gas to match, or buy a barrel that doesn’t suck. It seems that many barrels are ported to run steel case with an H3 and Sprinco Blue, because every dude on the internet is claiming that his setup is pure gold, so dudes are buying guns and throwing crazy shit in them. Its a snake eating its tail.

Sprinco springs rust. Fast. I get it, you want one because Mike Pannone likes them and they last forever. My Blue, Hot White, and White springs rusted significantly in about the lifespan of two Colt springs. So, they cost more and did not last longer. Yes, that rifle was abused somewhat. You guys in the desert can disregard, along with dudes that shoot in dry weather or at least dry and clean their guns immediately after use. Blue is too much, I’d choke down my gas if Blue runs well in adverse conditions. I liked the Hot White, a lot, because it goes into battery more vigorously, but that energy is coming out of the rearward half of the cycle.

Tubbs SS is too much in a Carbine sprung system. In an A5, the Tubbs is similar in strength bottomed out as a Colt spring, and a bit stronger in battery, as I’ve measured. So its not optimal as a solution, but it does work without adverse effects, in my A5 lower. I’m using a Tubbs SS on a dedicated suppressed rig, simply because it was a quick fix. I choked the gas down when I put the thing together, and it was still a little gassy. The spring works in this situation, but choking the gas back some more would 100% be the right answer. I’ve used other uppers, unsuppressed on this lower, and nothing crazy happened.

Searching for past comments about spring strength I found the above post. It’s curious that @1168 found the Tubb (AR15 I presume) spring too strong but not the Sprinco White (or Hot White even) as when new the White tested slightly stronger. Maybe one changes more with use. Incidentally both test a bit stronger than the JP Carbine spring so I guess that could be in an acceptable range according to him.

On the A5 system however it sounds like he would find the JP Rifle spring excessive at 12 to 13 percent stronger than the Tubb spring.

@Brahmzy Have you had any issues with corrosion in those 12+ years?

[Brahmzy]

Zero corrosion. ^^ that said Ilive at 6,800rt high desert. Super dry here. Good for all things metal.

I also will say I’ve got adjustable gas on almost all of my rifles. So they’re all tuned for cold, no lube, high-carbon, gummed up worse-case scenario.

I’ve had almost every kind of buffer spring made for testing kicks and always end up going back to the JP ones. Those Tubbs springs are strange beasts. I think they can work well, but it’s like a freakin’ fingernail/chalkboard thing to me.

If I were to go with mil-spec I’d probably look at V7’s Teflon-coated mil-spec ones.