130 grain TTSX in 30-06 groups opening up

Sounds like they are not stabilizing as they slow down, like the old style tops you spun by hand. As they slow, they wobble. Can you speed them up at all?

A 1-inch gun rarely shoots 2-inches at 200 yards and 3-inches at 300 yards. At first blush this linear relationship between range and group size seams reasonable but in reality it frequently is not. The farther the range the larger effect the wind has and this grows faster than linear since the bullet is slowing. The bullet covered the first 100 yard in less time then the second 100 yards. Instability issues (insufficient twist and/or imbalanced projectiles) will cause groups to grow faster than linear. Next shooting further is harder for the shooter. Seeing the target clearly become more challenging with range, heat mirage and similar distortion have a bigger effect at longer ranges and minor errors in the shooters technique get magnified by range. ie 200 yards is more than twice as hard as 100 yards.

Setting that aside when was the last time you de-coppered your barrel? That could cause accuracy issues too.

trapperjohn said:

my rounds are leaving the muzzle over 3200 ft/s. I thought about barrel fouling but only have under 100 rounds through the barrel since I last took it to bare steel

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At 3200+ fps with Barnes TTSX you might just be running into a copper fouling problem depending on how smooth that barrel it.

trapperjohn said:

It wasn't gusty that day, maybe 10 mph wind once in a while.

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All of the above, plus the effect of mirage and varying wind. Have been trying to figure out how to post a screen shot.....unsuccessfully.....but you can see what a mere 10 mph full value (@ 90* angle) will do to your bullet @ 200 & 300 yards. Take into account that you said the wind was variable from 0 (I think) to 10mph. So, if wind zero, no effect if 10 mph, based on my memory, a 130 gr. .308 bullet @ 3100 fps will be blown off course 2.5" @ 200 yards and over 9" @ 300. This plus your straight line double/triple 100 yd. group size. You can plug in your numbers @ https://www.norma.cc/us/Ammunition-Academy/Ballistics/ballistics-program/ and play with different wind velocities, bullet drop etc. out to 600 yards if you want to. Great tool. Be sure to click "imperial" at top of page or you'll get some really screwy answers.

Regards,
hps

People shoot those at similar speeds and don't have any issues. I'm loading 130's for my 308 @ 3050 fps and they group well enough at 200 yards. BUT, once I shoot up the ones I have I'm not going back to them. They work, but I can get better accuracy with other bullets that I just like better. Where I like the TTSX's is when using a cartridge normally considered too small for the game hunted. Using 243 on elk for example, the great penetration of the copper bullets is a plus. But I just think there are better options for 30-06 and normal North American game. In Alaska or Africa when hunting game where 30-06 is starting to be borderline then yes.

When I load 125gr 30-06 I've found the lower end worked better for me in milsurps, when I tried loading them hot the accuracy went away.