JP Enterprises Silent Capture Spring

[bwaites]

You can get your self a set of CS springs, and never worry about them again... Extractor, ejector and buffer would run you $40-50, and last you, your kids, and your grandkids the rest of their life.. Rated for Five hundred thousand (500,000) compression cycles at maximum performance...

Like this: http://www.davidtubb.com/ar-15-buffer-sp...ne-and-std

I'm always sceptical of those huge numbers of rounds. There is no way they shot 500,000 rounds to test them, because the cost of doing so outweighs possible profits so much.

Better yes, 490,000 rounds better? Doubt it.

[cory]

I'm always sceptical of those huge numbers of rounds. There is no way they shot 500,000 rounds to test them, because the cost of doing so outweighs possible profits so much.

Better yes, 490,000 rounds better? Doubt it.

I agree it's doubtful they've tested to that number, but not many companies test to the number they advertise. It's more of a design to. We have so much knowledge and experience with materials that it's not difficult to effectively design to a specific life span.

The fact that it wasn't tested to that number normally means a higher margin of safety. I would suspect with a number like 500,000 it was actually designed to infinite life. Will it really hold up that long? With no imperfections in the material or in the manufacturing process, probably.

[GMinor]

Probably a music wire spring. One guy here said he had 4" of shrinkage. That Is more than a good CS Spring will ever shrink.

[explorecaves]

I'm always sceptical of those huge numbers of rounds. There is no way they shot 500,000 rounds to test them, because the cost of doing so outweighs possible profits so much.

Better yes, 490,000 rounds better? Doubt it.

Easy to set up an automated machine to repeatedly compress a spring similar to the environment the spring would see in the rifle. Run the test through an environmental chamber at the same time to simulate temperature variations (seasons) throughout the year and you have a reasonable test that is repeatable giving you the data to average out the 500k round claim. This is a standard industry practice to extrapolate expected lifetime of any product.

[GMinor]

Easy to set up an automated machine to repeatedly compress a spring similar to the environment the spring would see in the rifle. Run the test through an environmental chamber at the same time to simulate temperature variations (seasons) throughout the year and you have a reasonable test that is repeatable giving you the data to average out the 500k round claim. This is a standard industry practice to extrapolate expected lifetime of any product.

Yes, bwaites, be realistic.

Easy enough to set up a machine that stresses the spring 500,000 times, let that pig run for a few days or weeks and bam. You have 500,000 compression cycles.

[GMinor]

Easy to set up an automated machine to repeatedly compress a spring similar to the environment the spring would see in the rifle. Run the test through an environmental chamber at the same time to simulate temperature variations (seasons) throughout the year and you have a reasonable test that is repeatable giving you the data to average out the 500k round claim. This is a standard industry practice to extrapolate expected lifetime of any product.

Yes, bwaites, be realistic.

Easy enough to set up a machine that stresses the spring 500,000 times, let that pig run for a few days or weeks and bam. You have 500,000 compression cycles.

[NugginFutz]

Easy to set up an automated machine to repeatedly compress a spring similar to the environment the spring would see in the rifle. Run the test through an environmental chamber at the same time to simulate temperature variations (seasons) throughout the year and you have a reasonable test that is repeatable giving you the data to average out the 500k round claim. This is a standard industry practice to extrapolate expected lifetime of any product.

Some of these test rigs are surprisingly unsophisticated. Simple motor, pulley and crankshaft with a counter, in many cases.

[GMinor]

Anyways. It is an option that many have not heard about. I am going to order 2 buffer springs, 2 ejector/extractor springs, and a SA R700 firing pin spring tomorrow direct from that website I linked to earlier. They offer a MIL discount, don't know what it is, but if I remember I will pass the info down after ordering.

[bwaites]

Yes, bwaites, be realistic.

Easy enough to set up a machine that stresses the spring 500,000 times, let that pig run for a few days or weeks and bam. You have 500,000 compression cycles.

Nope, thats not a valid test of life in a rifle where the temps vary by hundreds of degrees! It doesn't test exposure to chemicals, lubricants, cleaners, degreasers, then baking and freezing.

Checking compression cycles is all well and good, but it is most definitely NOT a test of real conditions inside a rifle.

Bill Alexander keeps finding all kinds of cool little things that SHOULDN'T affect rifle performance, but do. We actually know much less on some of these things than we think we do.

I think they are better springs, but 500,000 rounds is way out there! Why bother? No rifle made will ever see those numbers without failure, so why build the cheapest component to that standard?

I run them in a couple rilfes and I like them, but the numbers didn't make me decide that.

[jfornelli]

So, where have you folks been purchasing the silent capture spring? I've seen it directly through JP Enterprises as well as Midway and Brownells but am wondering if you've found a place that has a really great price. If not, they're all pretty close so it won't matter which one I go through.

[jfornelli]

Nevermind. I found several places but most were out of stock. The three places I mentioned all had it in stock so, being impatient, I bought two of them from Midway, which ended up being the overall cheapest (but only by about $3).