Gentlemen:

I have a Tikka TX3 in .308 which I’ve had for several years and which I’ve shot a lot. My favorite load was a 150 gr. NBT fueled by a moderate date of either Rl 15 or Varget, The load regularly performed admirably. At some point accuracy tailed off, and groups opened way up. I went through the usual drills to no avail. For the hell of it , I tried loading 165/168 gr Speer or Nosler, and suddenly accuracy returns, the first two touching and the third with in 3/4 “.

Any ideas about what’s going on?

Thanks,

Bob

I dunno - but if you're getting good accuracy with the 165/168 grain bullets, continue!

I've worn out a few 308 barrels, mostly with 168 gr match bullets, with a fair smattering of 165 gr hunting bullets. They performed very well on target and on game.

Regards, Guy

Scope and mounts? Barrel fouled? Stock screws loose? Lots of things it could be as well as a barrel that has been used.

How many rounds downrange? Is the new load same COL as the previous, or longer. What I am getting at is maybe the new load is chasing the lands, and the old load simply needs a longer COL to perform. Which would mean it will soon be time to shop for a new spout.

Youve shot it a lot, how many rounds down that tube? How do you clean the barrel, is it copper fouled. Switching bullets wouldnt affect accuracy if your mounts or scope are suspect. Its likely a really copper fouled barrel, different lot of bullets and powder and a worn throat.

You guys are confirming my belief that this barrel is checking out. I’ve played with screws, seating and charges. I’ve also scrubbed this barrel clean. I’m very pleased with the 165 accuracy, but as has been stated, the end is probably not far off.

Thanks for your info. Anyone with other ideas. Please feel free to comment.

Bob

The 308 has a very long barrel life upwards of 3,500+ rounds (for hunting) if not shot too hot or maxed out on pressure. I think you should check the throat and try seating the 150s longer. If you are convinced the barrel is going then I would try the Tubbs final finish on it. Some claim to have added at least a couple hundred more rounds to the useful life of the barrel. You will definitely want to seat the 150s longer and up the powder charge to get the same velocity you were getting previously. If after this it is still off then the barrel may be headed south, but you are only out of the cost of the FF kit and ammo to find out. Or just shoot the 165s.

One thing you might try is a few bore-lapping rounds. This slicks up an eroded throat, and while it may not bring the barrel back to its original accuracy, often comes close.

David Tubb (who knows a thing or two about accurate rifle shooting) sells a kit called "Final Finish" with enough abrasive-treated bullets to do the job. but you can also make your own bullets with a kit from NECO.

Have used both to treat barrels that had lost their original accuracy, and they've always helped.--at least the first time. Both cost a lot less than replacing a barrel.

Thanks for the additional suggestions gentlemen. Sounds like I need some Final Finish and some longer seating.

Best,

Bob

A 308 hunting barrel should last 8-10.000 rounds..


Check:
Scope
Rings
Recoil lug
Bedding in general
Is Barrel touching barrel channel
Is muzzle damaged
Is barrel clean or damaged in some way

One question perhaps out in left field: Are you loading from the same lot of 150 BT as when accuracy was great? If you are shooting Nosler blems or seconds, that could also be the issue. Happy Trails

Try a different 150 grain bullet?

Thanks again guys. All of the aforementioned have been done, but certainly could stand a second look.

Hanco, I've also tried Sierra 150’s and Nosler flat base 150s.

Bob

Its not just "blems or seconds" that you need to be mindful of, its also different lot numbers. Also, how far off the lands was the initial load that shot well, compared to how far off the lands now? Thats with the original 150 gr loading and the new 150gr loading with the same bullet. Thats critical information that should always be written down and recorded.

BSA:

Thanks for your input. I typically load .308s in this rifle out to max 2.810. I played with several different seating depths, but the results were the same. I’m about to settle for 165s and run some Tubb Final Finish down the tube.

B

If its shooting good with the 165's, id keep shooting them. However, its still a good idea to keep track of the distance off the lands. "Max 2.810" doesnt say anything about how far off the lands you are running them. A lot if guys just guess and by golly this schidt, rather than really know the useful information they need to know. If you keep some bullets out from the first lot you load and make note of max OAL, you can periodically check your rifle for throat wear. Its important if you like loading accurate ammo. If not, its not necessary. Recently i checked throat erosion on one of my creedmoor rifles that just turned 1,000 rounds downrange (now its at 1,200). The throat has eroded back .025" after 1000 rounds. I lengthened oal by that much so my ammo is .020" off the lands and that alone tightened the groups back up to where it was before (sub .8 moa 10 shot groups). Just something to think about.

The Tikka is a long action, so you could get a long action extractor and bolt stop to get the "full length" with a long action (30-06) magazine and parts. I have found that magazine length usually limits how far out one can seat a bullet. Often at magazine length long before hitting the lands.

Thank you guys more pertinent info and ideas to implement.

B

How would the rifle shoot 165 grn bullets so well if it had one of those issues?

McInnis, I don't know, perhaps you have a better suggestion.