SKS-FILES FORUM

SKS Carbines => Unaltered SKS Rifles => General SKS Discussion => Topic started by: Justin Hell on June 28, 2021, 02:39:20 PM

Title: CLOSE call.
Post by: Justin Hell on June 28, 2021, 02:39:20 PM
I just had a scary moment.
My newest SKS project, freshly fired a few days ago to confirm the build went well...was hanging above my cabin's back door.  I went out the door and hear a thud upon closing the door.  I opened the door and found it had fallen...it appeared as though the only damage was a stretched out clip on the sling and the cleaning rod (NC Star) had it's head pulled off...they don't machine them out of one piece anymore, the head is pressed on.  I found that the wall hangar design (homemade) had failed, this particular one I glued instead of screwing into place. No big deal...or so I thought.

Upon further inspection, I found that it had LOADED itself.  It hadn't kept it loaded all this time until I proved it wouldn't slam fire. The headspace is tight and despite it loading into battery, I had some concern that it was a touch TOO perfect.  Luckily it has a spring loaded Russian bolt....and it worked perfectly.  The thing fell hard enough to charge itself, but not slamfire. Which was a very good thing...as it also has 20 round star mag. The rubber mat on the floor where it fell and the Yugo buttpad didn't prevent it from the jolt being enough to ride the carrier back and load it.

WHEW!
Title: Re: CLOSE call.
Post by: Phosphorus32 on June 28, 2021, 02:55:14 PM
Wowza! That was exciting enough without a discharge. Glad it turned out okay.
Title: Re: CLOSE call.
Post by: running-man on June 28, 2021, 03:58:17 PM
Hey Justin,

Was this carbine in a closed bolt/chamber empty state (I guess this would be a condition 3 state with a loaded magazine inserted and no round in the chamber.) or was the bolt open and only being held open by the BHO feature?

I can easily see the latter causing a round to be loaded and have even seen videos of guys getting their guns to load from simple shocks that dislodges the BHO feature, but man I'm having a hard time visualizing how a bolt gets cycled from fully closed in a 8 foot fall.  I guess it would happen if the buttplate hits the ground at the perfect angle, but man that's got to be a hit by lightning type chance there. 
Title: Re: CLOSE call.
Post by: Justin Hell on June 28, 2021, 06:00:37 PM
Yep.
Closed bolt, empty chamber, magazine loaded.  I just loaded it the other day as this is the typical way I store most of my SKSs.
I don't leave the bolt open because its rather dusty here.
Trust me, I was as shocked as you are!   :o

It came down with enough force to rip the head clean off the rod...in fact, I still haven't found it. In order for that to happen one would assume it hit straight down.
The recoil spring came from a freshly gutted Canadian...probably unfired since refurb and import...and it feels just like charging any other SKS...
And yes, I am positive I didn't accidentally load it into the chamber when loading it...its a little harder to do the 'thumb on the top round' thing when closing the bolt with the 20 rounder...I distinctly remember it being a tad more difficult. 

It's one for the books, I doubt it will happen again...and I certainly won't be trying!
Short of a slight ding in the stock...it's no worse for wear.  Luckily I stocked up months ago on the cheapo NC Star cleaning rods.  :))
Title: Re: CLOSE call.
Post by: Greatguns on June 28, 2021, 06:29:38 PM
But is the SKS alright? :P

Seriously though, glad it didn't discharge or land on your head.
Title: Re: CLOSE call.
Post by: Justin Hell on June 28, 2021, 06:42:22 PM
She's just fine.
I probably would have broken the fall with my head and the door if I was entering, fortunately the wife and I had just exited...closed the door behind us...thud.
Crazy sauce.
Title: Re: CLOSE call.
Post by: Justin Hell on June 28, 2021, 07:10:14 PM
Now that I think about it...do you think the rubber floor mat that's a half inch thick combined with the butt pad on the Yugo stock could have actually amplified the force?
Title: Re: CLOSE call.
Post by: Phosphorus32 on June 28, 2021, 07:33:26 PM
Quote from: Justin Hell on June 28, 2021, 07:10:14 PM
Now that I think about it...do you think the rubber floor mat that's a half inch thick combined with the butt pad on the Yugo stock could have actually amplified the force?

That definitely wouldn't have amplified the force, but it likely prolonged the impulse. In other words, the energy was spread out a bit, such that it gave it time for the bcg to travel back far enough to clear the back of the round (~2.75" out of the full 3.5" of travel) and strip off one on it's way back forward. Doing a little testing on my bathroom scale (non-ideal) it took about 12 lbs of force to push it that far back, so there had to be a square hit on the butt with about 1.5g in force to multiply the 8 lb weight of your SKS and provide enough energy to compress that spring far enough. That is a completely believable scenario with a 6-8 foot drop of your SKS giving enough acceleration to obtain at least 1.5g.
Title: Re: CLOSE call.
Post by: Justin Hell on June 28, 2021, 09:37:24 PM
Quote from: Phosphorus32 on June 28, 2021, 07:33:26 PM
Quote from: Justin Hell on June 28, 2021, 07:10:14 PM
Now that I think about it...do you think the rubber floor mat that's a half inch thick combined with the butt pad on the Yugo stock could have actually amplified the force?

That definitely wouldn't have amplified the force, but it likely prolonged the impulse. In other words, the energy was spread out a bit, such that it gave it time for the bcg to travel back far enough to clear the back of the round (~2.75" out of the full 3.5" of travel) and strip off one on it's way back forward. Doing a little testing on my bathroom scale (non-ideal) it took about 12 lbs of force to push it that far back, so there had to be a square hit on the butt with about 1.5g in force to multiply the 8 lb weight of your SKS and provide enough energy to compress that spring far enough. That is a completely believable scenario with a 6-8 foot drop of your SKS giving enough acceleration to obtain at least 1.5g.

Wow...that is kinda what I meant. But a far better description of what I imagined. It's kind of shocking that could happen.  It's more surprising that it must have happened that way...precisely enough to ride the carrier back.  I am totally seeing why there isn't a cavalry that uses an SKS....  rofl

Makes you think...thankfully my afterthought didn't come with a higher price.

At least I know the thing is sound. The headspacing does leave very little room for error.  The early Russian bolt in an early 57 Chinese fit like it was made for it...better than actually. It flat out doesn't move.   If it fell hard enough to load...but not slamfire, it would seem as if the spring loaded firing pin did it's job no?  Then again, the physics isn't really my forte'.  :)
Title: Re: CLOSE call.
Post by: Bob_The_Student on June 28, 2021, 09:57:51 PM
I was going to ask if you pissed off the wife and was she inside when this happened.   wink1
Title: Re: CLOSE call.
Post by: Justin Hell on June 28, 2021, 10:24:36 PM
Quote from: Bob_The_Student on June 28, 2021, 09:57:51 PM
I was going to ask if you pissed off the wife and was she inside when this happened.   wink1

When this happened...we were totally getting along.
That's all I've got to say about that.  :))
Title: Re: CLOSE call.
Post by: Bacarnal on July 03, 2021, 04:21:46 PM
Next step...sage the house wink1
Title: Re: CLOSE call.
Post by: Phosphorus32 on July 03, 2021, 07:19:34 PM
Quote from: Justin Hell on June 28, 2021, 10:24:36 PM
Quote from: Bob_The_Student on June 28, 2021, 09:57:51 PM
I was going to ask if you pissed off the wife and was she inside when this happened.   wink1

When this happened...we were totally getting along.
That's all I've got to say about that.  :))

rofl chuckles1
Title: Re: CLOSE call.
Post by: Larry D. on July 04, 2021, 06:46:09 PM
Quote from: Justin Hell on June 28, 2021, 10:24:36 PM
Quote from: Bob_The_Student on June 28, 2021, 09:57:51 PM
I was going to ask if you pissed off the wife and was she inside when this happened.   wink1

When this happened...we were totally getting along.
That's all I've got to say about that.  :))

I noticed you used the past tense there.....
Title: Re: CLOSE call.
Post by: Justin Hell on July 04, 2021, 10:24:42 PM
Quote from: Larry D. on July 04, 2021, 06:46:09 PM
Quote from: Justin Hell on June 28, 2021, 10:24:36 PM
Quote from: Bob_The_Student on June 28, 2021, 09:57:51 PM
I was going to ask if you pissed off the wife and was she inside when this happened.   wink1

When this happened...we were totally getting along.
That's all I've got to say about that.  :))

I noticed you used the past tense there.....

Yup.... whew1