Not even on paper

[Sasquatch]

This is a first for me- I've had good luck doing optimal charge weight loads for 308 and 300 blackout. I've got a really accurate load for hunting with 308 and wanted to get some additional loads. I had picked up some Barnes TSX-FB 200 grain bullets at some point in the past (probably Gander out of business sale). Using Barnes load data I made up 5 loads to do some OCW on (as well as 5 loads of a different round I was testing). I shot the the other load and had some decent groupings for me to work on later. When I tried the 200 TSX I didn't hit the paper (8x11) at 100 yards. I tried three different loads, one shot each and never found the paper. I just wrote 'FAIL' on my notes and decided to pull the rounds. Just to make sure my scope didn't get knocked loose or something I tested with the known round and found bullseye.

How could a round be so inaccurate that it can't make 8(+) MOA? My buddy suggested doing some shorter ranges to see if it was really low (or high), but I didn't see the point. If I developed a load for it that required 32 clicks to hit at 100 yards I can't see it being worth using at all.

 

[Charlie R]

Are you sure that you are stabilizing the bullet? I have had that happen when trying to run heavy VLDs that I did not have the twist rate for. Not sure how long the Barnes Bullet is, but I would check stability. You can check stability using the JBM Stability Calculator here.

 

[Combat Diver]

I agree to move in closer or use a clean 4'x8' sheet of plywood as a backing for your target at 100yds. Different bullet weight and velocity = different point of impact. I've you happened to pick up some cheap Christmas wrapping paper, turn it backwards and use that.

CD

 

[Sasquatch]

Thanks for the link. The bullet length is 1.5" and I plugged in both min and max velocities from Barnes' data and it was in the yellow (just over 1.x) because it has a relatively slow twist rate (1:12). Also, the box says "1:10 twist or faster"

So- you might have hit on what's wrong- except the Barnes data itself was tested with a 1:12 barrel (with the 200 grain saying 1:10 recommended).

I think you're right though.

 

[Sasquatch]

I've got an AR10 with a 1:10 rate- I'll try the same bullets with that. Putting 1:10 into the calculator gives it a very nice 1.5 stability.

 

[Charlie R]

except the Barnes data itself was tested with a 1:12 barrel (with the 200 grain saying 1:10 recommended).

The barrel descriptions given in load data are to give you a base line for the velocities reported primarily, and cup pressure, not so much for grouping. The proving barrels that are used in labs are just another piece of test equipment to them, and that may explain the discrepancy you noted.

 

[Beef15]

Would bet it's a stability issue.
Might try closer to look for signs of wobble/tumbling.

 

[Toprudder]

Probably just saying something that others here already know, but I am a relative newbie to rifle as well and from what I have been reading, stability is more about the length of the bullet, not the weight. The significance here is that the Barnes bullets are solid copper, and since copper is less dense than lead, they have to be longer to be the same weight as a jacketed lead bullet. A 200 gn jacketed lead bullet may stabilize, where a solid copper bullet may not.

Having said that, barrel harmonics being what they are, it is entirely possible for the POI to move a few inches @100 yards. If you moved in to 50 or 25 yards (or use a bigger target at 100) and see keyholes, then the mystery is solved.

 

[Charlie R]

Probably just saying something that others here already know, but I am a relative newbie to rifle as well and from what I have been reading, stability is more about the length of the bullet, not the weight. The significance here is that the Barnes bullets are solid copper, and since copper is less dense than lead, they have to be longer to be the same weight as a jacketed lead bullet. A 200 gn jacketed lead bullet may stabilize, where a solid copper bullet may not.

I did not know it was a solid copper bullet, but your reasoning is 100% correct. Good points all.

 

[11B CIB]

Came here to mention the point about the solid copper slug. I’ve just started working with some 62gr TTSX and cant find much at all out there with people loading them.

Barnes load data mentions SIGNIFICANT differences between .223 and 5.56 data; several grains worth of powder.

Very unique bullets