Shocking Aquila Ammo-question

[Byrd]

At the range this week a friend brought a box of the Aquila super sonic (wrong name?) ammo that shocked us both...at 50 ft. out of his Bersa and my Beretta M21 it punched holes in the paper the size of .38 wadcutters, so it was expanding BEFORE it hit the paper! Out of my S&W m34 with 4 in bbl. it punched standard size .22 holes! What gives? Has anyone ever had this happen to them, it was not a fluke because it did it consistantly!

[Darrell]

I'm guessing it was keyholing. Which means the bullets were tumbling end over end. Most likely they were not stablizing from the shorter barrels.
Twist rate of the barrels could have something to do with it also.
What grain are the bullets?

[Jericho]

I would have to agree with Darrel, I think it has to do with the short barrel. Whose bullets travel so fast that they would shoot 2" high at 100 yards for me (from the normal hi-velocity ammo that I shoot). I would say that it is not getting the proper twist that it needs to fly like it should.

[Byrd]

They were not keyholing-the hole in the target was a perfect circle with no indication of tumbling, out of the Bersa they were very accurate, my Beretta was average. I think they are 30 grain bullets. I am still puzzled as to why they would leave a hole that looked like a .38 cal wadcutter. Are shorter barreled guns rifled with a faster twist maybe? Could it be possible they were expanding before they hit the paper? I have never seen anything like this before and this is my first experience with Aquila ammo.

[awp101]

Supersonic or SUBsonic?

They are not expanding before hitting anything though. I've heard of rounds loaded too hot to vaporize before hitting a target (mainly varmint and very hot AR handloads) but that still wouldn't cause what you're seeing.

The Aguila Sniper Subsonic requires a certain twist rate to properly stabilize for best accuracy, so the supersonic may be rate specific as well. Shorter bbls don't necessesarily have a faster twist but what they DO lack is room to maximize the twist. Here's an example:

If a bbl is rated as a 1-12 twist that means the bullet will make one revolution per 12" of travel.

If we take a 12" bbl, the bullet will get a full revolution BEFORE it leaves the bbl which makes it more stable.

If we cut the bbl down to 3" then the bullet will only get 1/4 revolution before leaving the bbl (12 divided by 3 equals 4) which makes it less stable because it didn't get that full revolution before being subjected to the outside world.

These are the basics of the theory but it's a solid foundation to build upon. After the bullet leaves the bbl wind, muzzle blast, gravity, etc will affect bullet stability but that's a lecture for another time and place.

Besides, my brain hurts now...

HTH!

[Byrd]

They were the Supersonic rounds-very accurate out of my friends Bersa-1 1/2 groups @ 50ft. I understands the bbl. twist, but I guess I am going to have to buy a brick of these things and try them out. I am guessing that because of the accuracy out of the Bersa they were stabilizing in the bbl. My Beretta M21 is not accurate at that distance with anything...4-5 in groups is the norm. But out of both pistols they left a perfect .38 wadcutter size hole! My S&W M34 has a one in. longer than the Bersa and it showed no indication of the larger holes. I guess this is a shooters mystery!

[63DH8]

Pistols will not allow cartridges to accelerate to max velocities. Ammo makers use rifles with 22, 24, and up to 26 inch barrels. They usually post the barrel length in with what the velocity list. If they don't, assume they used a barrel length that will give their ammo the best result; Usually 16 inch for centerfire and 24 inch for 22rimfire.

The general rule of thumb is you will lose 100fps per inch of barrel loss until you get to the pressure of the case upon ignition (In reality, the drop is not liner). If I remember correctly, the Agula rates their top speed .22 around 1700 fps. You said your pistol barrel is how long? I'm sure Agula tested their rounds in a rifle to give it the maximum velocity. I'd say a 26 inch, but I'll give them the benifit of the doubt of 22 inch. You can see how much of a drop in velocity you'll have with a pistol in comparison to a rifle.

Now think, if the bullet is "expanding" with a pistol, it would it hold together when fired through a rifle?

More than likely, I would say the target wasn't supported where the round made a ".38 cal" hole. With no backing, the paper will push back and create a larger hole than if the target was solidly backed with wood or something else solid. If you go shooting again and place two targets up with one paper target supported with a simple "T" type holder and another with a sheet of plywood with no holes, you'll notice larger holes on the target that's unsupported. More than likely, when you fired your pistol, there was nothing or a hole behind the impact area. That would create the larger hole. Been there, done that, questioned it, tried it, confirmed it.

[Byrd]

You are correct-the target was unsupported-I will give it a try @ the next range trip. I think I will also put some newspapers in a box to catch the round and see what that tells me...I am still perplexed though! Thanks for the comments!

[ugly Finn]

Originally Posted by 63DH8

Pistols will not allow cartridges to accelerate to max velocities. Ammo makers use rifles with 22, 24, and up to 26 inch barrels. They usually post the barrel length in with what the velocity list. If they don't, assume they used a barrel length that will give their ammo the best result; Usually 16 inch for centerfire and 24 inch for 22rimfire.

The general rule of thumb is you will lose 100fps per inch of barrel loss until you get to the pressure of the case upon ignition (In reality, the drop is not liner). If I remember correctly, the Agula rates their top speed .22 around 1700 fps. You said your pistol barrel is how long? I'm sure Agula tested their rounds in a rifle to give it the maximum velocity. I'd say a 26 inch, but I'll give them the benifit of the doubt of 22 inch. You can see how much of a drop in velocity you'll have with a pistol in comparison to a rifle.

Matter is bit more complex. Actually in rimfire bullet needs only about 10" long barrel to get max velocity, it will start to slow down after that point.
Best accuracy does not necessarily need one full revolution to bullet in a barrel, usually slower ammo will do just fine even barrel is shorten.

Biggest problem, i think, is that time period when bullet travels in barrel is about three times longer than in most centerfire rifles. We shooters are unstable creatures and can't hold a gun absolutely still that long, atleast I can't. Very tiny movement can cause quite good flier.
Using hi-velocity ammo will give us smaller time periods and we see that as a smaller groups. But it doesn't mean that hi-velocity ammo is more accurate, we just make less errors.

Pete

[allamerican]

I had the same thing shoting supermax aguila out of a beretta 21. I had a backing but the holes were perfectly round and about .32 calibre.