Abnormally fast 6mm Rem Load?

[Marksman]

I had a chance to get out to the range this weekend with my chrony to check some loads. I was rather surprised at the reading I was getting with my 6mm Rem load. With the chrony set at 15', and me using my 25" barrel, shooting 55 Nosler BT. I was shooting 52 gr of H-380 and was getting speeds that averaged 4352 fps. And that's with no pressure signs, and still 1 whole grain under the Hodgdon maximum load listed.

Any thoughts on why this load is shooting so fast?

 

[snert]

Altitude?

Sounds like a chrono issue to me

 

[dragman]

zero it and shoot it out at 500 verify the drop and see what that tells you for speed. I think the readings are just off on your chrono.

 

[CatShooter]

Altitude?

Sounds like a chrono issue to me

Nah... pulled the trigger too hard!

 

[Brians356]

I suggest you move the sky screens a little farther away if the cord is long enough. I've seen muzzle blast or whatever affect readings, and increasing the distance a bit solved it. It's may no make sense, but it's worth a try.

 

[Lapua40X]

I'd find a chronograph to compare readings with the one used here. Those numbers just don't shake out quite right.

 

[ARW]

I'm really interested in how you make out with this, please post the outcome.

My father shoots the same bullet in his 6mm Rem and is getting some very impressive speeds out of it.

Quite a while back, he called Winchester directly and got a load from them for W760 for this bullet, and if memory serves me correctly he was also getting very close to the speeds you are and also without pressure signs.

Alan

 

[4xforfun]

Altitude?

Sounds like a chrono issue to me

What would Altitude have to do with anything at 15'???

Agree 100% with the chrono statement.

 

[tiny68]

My guess is that it was a Shooting Chony that wasn't completely unfolded. I have gotten similar high readings when mine was in the full open position.

I had a 6 mm rem that I was sending to Dave Tooley to rebarrel and I needed to shoot the barrel out to justify sending it off (to my wife). I had four boxes of 55 Noslers and I tried to reach the max speed with every powder I had. I was flattening most primers. I never crossed 4200 fps and I was way beyond book max. I did manage to move the throat forward almost 2" so I say mission accomplished....

Luck, Tim

 

[Brians356]

I had a 6 mm rem that I was sending to Dave Tooley to rebarrel and I needed to shoot the barrel out to justify sending it off (to my wife).

How would your wife ever have known if it was actually shot out? Or does she reload and measure chamber throats etc herself? Or you simply cannot embellish the truth?

 

[tiny68]

I had a 6 mm rem that I was sending to Dave Tooley to rebarrel and I needed to shoot the barrel out to justify sending it off (to my wife).

How would your wife ever have known if it was actually shot out? Or does she reload and measure chamber throats etc herself? Or you simply cannot embellish the truth?

That was a time in life with 2 young children and not a lot of play money. The $800 I spent to have Tooley rebarrel and true up the action was a chuck of change and my first re barrel. Not sure what you mean your statement.

 

[bigedp51]

Altitude?

Sounds like a chrono issue to me

Nah... pulled the trigger too hard!

CatShooter the OP should watch the bullet as it leaves the barrel, if he sees a blue red shift in colors then the bullet is reaching the speed of light. (or else the OP lubed his bullets) :

Bazinga

 

[Brians356]

Not sure what you mean your statement.

Ditto.

Seriously, you had to actually have a shot-out barrel to be able to say "Honey, I need to replace a shot-out barrel"?

 

[tiny68]

Not sure what you mean your statement.

Ditto.

Seriously, you had to actually have a shot-out barrel to be able to say "Honey, I need to replace a shot-out barrel"?

Of course not. It was I time in life when was having a hard time justifying such a decision. Personally would have never spent that much in anything without having a discussion with my wife. She comes from a home that has avid shooters and supported my hobbies. "Why do you need this" is a valid question when $$$ is tight.

 

[Marksman]

I managed to get out and re-test my loads today. I ran them against both my new and old chrony and they both averaged 4250 fps. Almost exactly 100 fps slower than before. I also test some other loads from that same day and found they all ran 100 fps slower as well. Maybe I had the chrony set up wrong? Who knows. I guess this is always why you should check and recheck your data.

 

[william5409]

Sounds like a chrono issue to me

 

[Webster]

Try the chono when it's cloudy. No bright sun to cause false triggering. The sun reflecting off of the side of the bullet into the sensor can cause problems. I have gotten sensible chrono numbers around 12 to 2 in the after noon. On the same day when the sun angle was at about 3 o'clock I started getting strange numbers. Sun screens only help if the sun is overhead.

I shot a 6mm. Rem for many years. I shot only 75 & 85 gr bullets with mostly 4350 powder. Chono'd many 75 gr loads. I don't have my data any more but I am sure I never got over about 3350 (75 gr bullet) with a hot load. The Berger reload manual gives about 3650 fps max load with a 60 gr. bullet. I doubt your 500 fps more with a 55 gr. bullet.

 

[Barlow]

4250 or 4350, that's smokin. Barlow

 

[Titan700]

Another trick I have learned is to paint the bullet with a dark maker