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Discussion Starter #1
Couple of newbie questions and sorry if these are repeated from other threads.


1. Is it normal to have play between lower and upper receiver? If so, how much?

2. is it ideal to store it on safe, cocked? Or should I dry fire it?

3. How often do you clean gas piston? (After 20 rounds I couldn't believe how dirty it was, but rest of gun looked the same as after cleaning)

4. Debating on having a mag with Winchester PDX Defense on hand for SHTF scenario. Good idea?

Absolutely love the 17s!! Hell'a fun to shoot!!
 

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I always store my ARs and now my Mk 17 with the hammers dropped and on semi. Admittedly, that's a carryover from my Army days. As long as you verify the chamber is clear prior to storing, I suppose it doesn't make any difference either way.
 
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I also store my ARs and 17 with the chambers empty and the hammers dropped. A matter of what you are use to.
I check the gas piston on my 17 when I clean it. Old habits (M14) die hard.
 

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Couple of newbie questions and sorry if these are repeated from other threads.

3. How often do you clean gas piston? (After 20 rounds I couldn't believe how dirty it was, but rest of gun looked the same as after cleaning

Absolutely love the 17s!! Hell'a fun to shoot!!
You should see it after 100-200 rounds. I didn't clean mine until after the first 200 or so. And it is a blast to shoot, isn't it! Welcome to the forum!:shock:
 

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I never leave anything with tension on a spring. That means I never leave a hammer back (unless I am actively using the weapon) and I never leave rounds in a magazine any longer than necessary. If you want to keep one mag full just know that you are causing it to wear out faster than a magazine that is left empty. I know alot of people leave some mags full, and in general they still work fine.

I don't clean my piston that often. Maybe every 1500 rounds or so. Never had any problems with it.

Always a little play between parts. It shouldn't wiggle to the point that it makes noise.
 
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1)Mine wiggle a little. Not much though, not enough to rattle but there's definitely some movement when you apply opposing pressure on the upper and lower.

2)Like most here, I store all my rifles decocked; out of force of habit than any real reason. Dry fire as much as you like. Modern centerfire munition guns can be safely dry fired.

3)It gets pretty dirty in there but doesn't really impede the function in significant ways. I usually go several hundred rounds before thinking about cleaning with the AK and the piston AR. Just drop that thing in a bottle of solvent and brush the carbon off after a hour.

4)That depends on what your "AO" is like. I personally don't think the 17S is suitable for HD or even SHTF situation in a urban environment.
 

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I never leave anything with tension on a spring. That means I never leave a hammer back (unless I am actively using the weapon) and I never leave rounds in a magazine any longer than necessary. If you want to keep one mag full just know that you are causing it to wear out faster than a magazine that is left empty. I know alot of people leave some mags full, and in general they still work fine.

I don't clean my piston that often. Maybe every 1500 rounds or so. Never had any problems with it.

Always a little play between parts. It shouldn't wiggle to the point that it makes noise.
The science is clear on springs, your mags and springs wear out faster from loading and unloading.

Leaving a mag loaded does not degrade the spring appreciably.

You can have two mags 80 years old. The one left fully loaded will perform the same as the one never loaded.
 

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The science is clear on springs, your mags and springs wear out faster from loading and unloading.

Leaving a mag loaded does not degrade the spring appreciably.

You can have two mags 80 years old. The one left fully loaded will perform the same as the one never loaded.
This is true, you put more wear on a modern gun spring by cycling it, then if you leave it compressed. Not that it matters in this context.
 

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The science is clear on springs, your mags and springs wear out faster from loading and unloading.

Leaving a mag loaded does not degrade the spring appreciably.

You can have two mags 80 years old. The one left fully loaded will perform the same as the one never loaded.
I had heard the myth you are repeating multiple times before. I asked my dad who is a metallurgist for a definitive answer. It is true that loading and unloading a spring is the most damaging, however a spring under pressure will eventually deform and lose tension. So no, a full and an empty magazine left for 100 years will not be the same. If you measured the springs one would be more degraded than the other.
 

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I had heard the myth you are repeating multiple times before. I asked my dad who is a metallurgist for a definitive answer. It is true that loading and unloading a spring is the most damaging, however a spring under pressure will eventually deform and lose tension. So no, a full and an empty magazine left for 100 years will not be the same. If you measured the springs one would be more degraded than the other.

I don't know your father, no disrespect.

I can tell you that good springs are pre-relaxed and the resulting permanent deflection remains ~static after this initial tempering at normal temperatures. Factors time, and more so temperature (oven temps not earth surface temps) do have an effect, but time is largely irrelevant given that you will get more than a lifetime of service out of a properly made modern mag spring that remains compressed for that entire time.



Plasticity is measurable after a decade but only with meters, not noticeable in function.

The fatigue from unloading them far outweighs any loss in elasticity from long term compression.

I can't recall all the engineering details, but I do recall the Soderberg Criterion, Goodman Data, and others were the basis for these conclusions. There were some calculators that made use of this study data that could demonstrate and predict with amazing accuracy the behavior of springs under varying conditions.

Here's one study that shows some relaxation data, as you notice it takes heat:
http://www.db-thueringen.de/servlets/DerivateServlet/Derivate-24673/ilm1-2011iwk-064.pdf
 

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So you agree that a non-relaxed spring does lose plasticity compared to a relaxed one. :) The mags will still work, but you can measure (and calculate) the loss over time.
 

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No, it loses elasticity.

However, unloading your mags fatigues the springs. This causes far more loss of function than leaving them compressed could in a lifetime.

I unload my mags still. To clean them when necessary.

Not to avoid having a compressed spring. That's like finding a hole in your shirt and using scissors to cut it out.
 

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Discussion Starter #14
Thank you everyone for the great replies! The debate on springs is certainly interesting. Never gave that much thoUght till now. Don't thing it will change the fact that I have a loaded 1911 in my nightstand tho!!

I agree with the comment on a .308 not best suited in urban environment. Just interesting how the PDX performed in not over penetrating.
 
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