300 BLK tumbling?!?

[RHelton10]

Update on post #25

Looking for some advice and insight on why I have 220 grain factory loaded 300 BLK tumbling at 50 feet (can tell by the way the bullet is impacting the paper target at an indoor range)

Here are the specs:

• Barrel was cut down to 9.5" and rethreaded to 1/2"x28 but a local and very reputable gun shop. Unsure of the twist rate as it was on the part of the barrel that was cut off, but it was a factory barrel so assume 1:7 or 1:8
• Was shooting through a 9mm suppressor and cannot see any baffle strikes
• Have ONLY shot 220 grain bullets so far

I've read that 300 blk can be shot all the way down to around 6/6.5" so I don't think it's the barrel length (10.5" is pretty much the perfect length for it so I'm only 1" off). Barrel cut was professionally done by someone we all know and trust so I don't think or the crown is a problem. I'm a little surprised that it's able to make a complete tumble in such a short distance, but I'm getting slots in the paper instead of holes. I'd say 75% of roughly 30 rounds ended up like this.

Any thoughts? I'm going to take it back to the range and try another weight bullet, but that was all I had with me. I was really only there to sight in the rifle and wasn't expecting to have this problem.

 

[CBH13]

are you completely sure its tumbling? hard to tell without pictures. but a 220 grain is going nice and slow and will have an easier time ripping the paper as it passes through. you can tape the target to a piece of card board to be sure. now if they are looking like sideways bullets then everything im sayings totally invalid and i aint got a clue

 

[Duce4trey]

pics would help.

since the barrel was cut down what is the gas system length? (pistol, carbine, etc.)

 

[rOmiLaYu]

Do you have pics of the target? I'm having a hard time with the lack of baffle strikes and tumbling. Barrel length is fine.

 

[jeep78]

Call your "local and very reputable gun shop" and ask them. They would be the most knowledgeable folks on this problem.

 

[rOmiLaYu]

pics would help.

since the barrel was cut down what is the gas system length? (pistol, carbine, etc.)

A 9" barrel can only have a pistol gas system.

 

[Duce4trey]

A 9" barrel can only have a pistol gas system.

I definitely do not have my thinking hat on.
You are correct.

 

[fast306stang]

I would suggest shooting unsuppressed and see if you still have the same problem, that way you can eliminate the can as being suspect.

 

[RHelton10]

I'll be honest - it didn't dawn me at that time to take pictures. But I can say this; the targets are paper taped on to cardboard, and there was a day and night difference between the nice, clean, round holes when it did go in straight, vs the almost rectangular slotted holes that were roughly 1" across when it went in sideways. No doubt in my mind, the bullets were tumbling. I'm just not sure how or why...

I will be trying a different weight bullet soon to see what happens and will update. Was just looking for some ideas of what may be going on with the 220 grains that I need for suppressed shooting

 

[Tusker6N]

I agreed with shooting without the can...I'm thinking:
1. Crown is screwed up
2. Barrel isn't concentric where it was cut off