Swiss Arms Over The Beach Shooting UPDATE, Final Results and Conclusions Post #108

[vagrant]

Good work, I'm happy to see that it did in fact bulge. I was told it would do it by credible source, and the reason was logical, but to actucally see it confirms it. Thanks you, great testing and stay safe

 

[Steve Janes]

That's what MFS and Norinco ammo does to your barrel. Save a little now, pay a lot later.


Steve, Just wondering if you replaced your barrel with another SA barrel but just with 1:10 this time or if you had a custom made?

Do you think a gunsmith could figure out a way to build a barrel to eliminate the poi shift when going from bipod to shooting off the mag?
Or figure a way to build a barrel that would allow a free float forend to be mounted. I know a piston operated rifle can't truly be floated like a bolt gun but just something that would allow bipod use without it putting pressure on the end of the barrel.
I've see the Troy battle rail system but haven't seen anything in Canada about it being available to us and I don't want to add a bunch of weight to the rifle. I don't need a bunch of rails just something to support the forend.
I noticed with mine the other day that I get a 5 inch poi shift at 100yds, so far it is the only downside to the rifle and I know it happens with other rifles but I've never experience this much poi shift. On the + side I was on my way to a 5 shot cloverleaf group at 100yds but got a flier that landed 3 inches to the left of the cluster, probably my error and the AE 55gr. Was getting around 2900fps with that from the 20 inch barrel. I'm looking forward to trying some good ammo in it and also putting together some handloads for it.

Yes new barrel is a factory 1in10" twist OEM Swiss Arms barrel barrel.

As far as everything else, No, free floating the barrel is not an option and it's not necessary either. I have only experienced this POI shift when bench rest shooting. When using the rifle practically, it has never negatively affected my accuracy.

How much did that "experiment" end up costing you?

As I explained in the write up, I had intention of replacing my 1in7" twist with a new 1in10" twist and this was the only reason I felt the 1in7 was expendable. So I had intent on spending the money to do this regardless of what happened over the course of the test.

That being said, a new Swiss barrel sots $825, plus maintenance, and shipping.

I don't know, to me it just looks like some guy trying to live out his G.I. Joe / Mall Ninja / Zombie fantacies.

Funny, I didn't think zombies could swim???

Seriously though, thanks very much for the encouragement! Hope you enjoyed the video

 

[j_san]

Thanks Steve, after revisiting this thread a few times (and as a SAN owner) I found it informative.
I appreciate you being the "guinea pig" lol

 

[OccasionallyOnTarget]

Interesting experiment.

 

[NavyCuda]

I don't know, to me it just looks like some guy trying to live out his G.I. Joe / Mall Ninja / Zombie fantacies.

What is your point? Is it just to look down on someone else because you don't like what they do?

 

[TV-PressPass]

What is your point? Is it just to look down on someone else because you don't like what they do?

Haters gonna hate. It's the way of the interwebs.

 

[Dsiwy]

Great post Glad you have that kind of money to play with Very happy you were not hurt or had serious damage to your PE90

Reminds me of the AKs the ANA had, where they put cigarette butts in the muzzle to prevent sand from getting in. Turn out "suprise suprise" the barrels all bulged from them doing this. It does not take much to put stress on a barrel and alot of times you will only see a dark ring in your barrel from it.

This is a great wake call to people who think piston guns are water proof.

 

[Dsiwy]

I don't know, to me it just looks like some guy trying to live out his G.I. Joe / Mall Ninja / Zombie fantacies.

unless you drive a Kia the you cant say a thing

Sports cars are for race car wannabees
Trucks are for farmer wannabees
SUVs are for soccer moms trying to be cool
Jeeps are for army offroad wannabees
harleys are for HA wannabees
Sport bikes are for racing wannabees

Eveyone is a wannabee and its fun

 

[NavyCuda]

Great post Glad you have that kind of money to play with Very happy you were not hurt or had serious damage to your PE90

Reminds me of the AKs the ANA had, where they put cigarette butts in the muzzle to prevent sand from getting in. Turn out "suprise suprise" the barrels all bulged from them doing this. It does not take much to put stress on a barrel and alot of times you will only see a dark ring in your barrel from it.

This is a great wake call to people who think piston guns are water proof.

This has me wondering, would a subsonic rifle load have the same problem?

 

[Dsiwy]

This has me wondering, would a subsonic rifle load have the same problem?

I would say a subsonic would be better, less pressure less stress.

 

[NavyCuda]

I would say a subsonic would be better, less pressure less stress.

That mythbusters episode where they tested pistol against rifle in water and found the faster the projectile is going the faster it gives off its energy. So it would be very intererting to see how a subsonic .300blk rifle would handle this test.

 

[Sakonut]

I would love for somebody to attempt an explanation on how cheap ammo wears out a barrel faster than expensive ammo, especially in this case where corrosive/non corrosive isn't a factor. I call BS...

 

[dbala]

8000rds seems low in terms of barrel life unless shooting hotter rounds - no? I have close to that on my swiss rifle (only bulk factory 55gr & 62gr) and have noticed zero change in performance/accuracy out to 200m. To the OP - what made you think the barrel was shot out & worth destroying? Did you see a big drop in accuracy/performance?

 

[Dsiwy]

That mythbusters episode where they tested pistol against rifle in water and found the faster the projectile is going the faster it gives off its energy. So it would be very intererting to see how a subsonic .300blk rifle would handle this test.

Mythbusters only tested external ballistics under water, Internal ballistics under water is totally different.

 

[NavyCuda]

Mythbusters only tested external ballistics under water, Internal ballistics under water is totally different.

As long as the projectile is moving the volume of liquid below the maximum capabilities of the liquid to flow through the bore, no damage should occur. In this case the projectile is nothing more than the piston of a hyraulic ram. There is a point where the resistance to flow is enough to momentarly stop the flow of fluid, this is how the barrel would bulge.

On our machine if you're not careful going down a grade, the hydraulic system can surge and lock up the wheels and thus try to eject the operator.

 

[CarbineOne]

Go read the SiG field manual; It specifies an 8000 round barrel life.


This is what SiG/Swiss Arms states as their replacement point/accurate life of the barrel. You can shoot the barrel well in excess of 20k rounds.

 

[dizzy]

As long as the projectile is moving the volume of liquid below the maximum capabilities of the liquid to flow through the bore, no damage should occur. In this case the projectile is nothing more than the piston of a hyraulic ram. There is a point where the resistance to flow is enough to momentarly stop the flow of fluid, this is how the barrel would bulge.

On our machine if you're not careful going down a grade, the hydraulic system can surge and lock up the wheels and thus try to eject the operator.

There is a big difference between a piston in a hydraulic ram and projectile acting as a piston, and it has to do with shape. A flat piston head exerts force differently than a pointed piston does.

 

[Steve Janes]

I would love for somebody to attempt an explanation on how cheap ammo wears out a barrel faster than expensive ammo, especially in this case where corrosive/non corrosive isn't a factor. I call BS...

Call it whatever you'd like. As I said before, it's more than just just cheap ammo that caused the throat erosion. The Norinco yellow box ammo has very inconsistent bullet diameter. Some have been measured and a large portion are found to have undersized projectiles, some as small as .222. Sometimes 10 rounds out of 20 were like this. Sometimes only 1 or 2. I shot about 7-8k of this ammo through the rifle, and this is this that we speculate has worn out the chamber end of the barrel quicker than normal. The rest of the damage was caused by the OVB test. Also, let's make something clear here, the rifling at the chamber end was still there, not completely gone, it was just wearing way faster than normal.

8000rds seems low in terms of barrel life unless shooting hotter rounds - no? I have close to that on my swiss rifle (only bulk factory 55gr & 62gr) and have noticed zero change in performance/accuracy out to 200m. To the OP - what made you think the barrel was shot out & worth destroying? Did you see a big drop in accuracy/performance?

The Norinco IS hotter. Velocity is sometimes as high as 3200FPS, combine this with undersized projectiles bouncing around in the barrel like BB's.....

I did not think it was shot out (I only found that out after it was examined by the gun smith). I decided it was worth taking a risk on destroying it when I made the choice to buy a new barrel. An old barrel is exactly that, an old barrel, it's useless to me. No one would have wanted to buy a 1in7" twist Swiss barrel with 8000+ rounds through it. So why not get something out of it buy risking it on a destructive test and sharing the results?

Go read the SiG field manual; It specifies an 8000 round barrel life.


This is what SiG/Swiss Arms states as their replacement point/accurate life of the barrel. You can shoot the barrel well in excess of 20k rounds.

Also, what this guy said ^^^^^, holds some truth, while I've never read the 8000 round count for barrel life (I've read that number being closer to 15,000). This being said, the barrel may survive 30-50,000 rounds, this doesn't mean it will maintain the same accuracy as day 1.

 

[beltfed]

I would love for somebody to attempt an explanation on how cheap ammo wears out a barrel faster than expensive ammo, especially in this case where corrosive/non corrosive isn't a factor. I call BS...

For starters, Cheaper ammo means cheaper products used in general.
Most high-end powders burn cooler, allowing for more rounds to be fired overall.

Throat errosion is measured in seconds of high temp/high preasure rounds going off, and each round is measured in micro seconds.
The area of throat errosion is limited by the bullet acting as a plug. Remove this plug as is the case with blanks (although blanks use less powder charges than regular rounds) or undersized bullets, and the area of the barrel subjected to the errosion grows.
Additionally, brass cases act as heat sinks. Brass cases remove HUGE amounts of heat away from the throat on every firing. Steel cases perform nowhere near as good as brass in this regard.

The lands and grooves of the rifling are designed to cut into the bullet jacket and impart twist. As the bullet travels down the barrel it is gliding on the lands and grooves as if on rails. It should be consistant from round to round (both in concentricity/size of the bullet and the makeup of the jacket).
Undersized bullets would simply shoot down the barrel likely bouncing back and forth and scrape by the lands and grooves loosing jacket on its path and damaging the barrel as it goes.
Poorer quality jacket gilding will be stripped off into the rifling and add to the material in the bore as more and more rounds pass over top.

 

[Steve Janes]

For starters, Cheaper ammo means cheaper products used in general.
Most high-end powders burn cooler, allowing for more rounds to be fired overall.

Throat errosion is measured in seconds of high temp/high preasure rounds going off, and each round is measured in micro seconds.
The area of throat errosion is limited by the bullet acting as a plug. Remove this plug as is the case with blanks (although blanks use less powder charges than regular rounds) or undersized bullets, and the area of the barrel subjected to the errosion grows.
Additionally, brass cases act as heat sinks. Brass cases remove HUGE amounts of heat away from the throat on every firing. Steel cases perform nowhere near as good as brass in this regard.

The lands and grooves of the rifling are designed to cut into the bullet jacket and impart twist. As the bullet travels down the barrel it is gliding on the lands and grooves as if on rails. It should be consistant from round to round (both in concentricity/size of the bullet and the makeup of the jacket).
Undersized bullets would simply shoot down the barrel likely bouncing back and forth and scrape by the lands and grooves loosing jacket on its path and damaging the barrel as it goes.
Poorer quality jacket gilding will be stripped off into the rifling and add to the material in the bore as more and more rounds pass over top.

Another informed, valid, and appreciated opinion, from an experienced shooter.

Thank you, BeltFed