Years ago, I bought some Parker Hale target barrels from Sarco for cheap. I barreled several of them up on Mauser actions and every one of them shot sub 1" groups. I usually used 168 SMK bullets and congratulated myself on building target rifles on the cheap. I never shot them at longer than 100 yds as I never really had a need to. Flash forward to present. I signed up to take a long-range shooting class in April and I dug out two of the most accurate of the 4 that I built. Since the class will teach shooting out to 1000 yds. I decided to work up a load using the 175 gr SMK and soon found one that both rifles shot sub 3/4" @ 100 and I figured I was gold. A couple of weeks ago, I was reading a post that identified that the P/H barrels were 1-14 twist and even I know that this is not appropriate for the 175 and that somewhere out there, those bullets were going to become inaccurate. I measured the twist in both barrels and they are 1-14. As of today, I shot out to 300 yds and the bullets are still grouping with no sign of yaw. With no real long distance experience, I am wondering if anyone here might have an idea at what range could you generally expect to start seeing degradation of accuracy/bullet stabilization with the above mentioned load? Thanks, Lee.

The optimum twist rate for this bullet would be ~1:11.5" or faster, but your 1:14" barrel will still group these bullets well, until they tumble. This bullet is marginally stable in your gun (SG-1.05)

Suboptimally stabilized bullets will wobble slightly until they go trans-sonic or subsonic, wherein they are at risk for tumbling.

The trans-sonic distance will depend upon altitude, temperature, and velocity, and for most 308 target cartridges this will be beyond 1000 yds.

The slight wobble from your 1:14" barrel will increase the BC slightly (~14%). and hence, effect trajectory and wind bucking qualities.

Nonetheless, I suggest trying these bullets and see how they work at 1000 yds. They may be OK.

You might also go to a lighter bullet, such as the Berger 155.5 gr Fullbore, but even then SG = 1.12 with 11% compromise of BC.

Don't know the temperature when you tested them, but be aware that higher air density (colder air) could also have make them more unstable with that slow twist.

Clarence

I have had good success with a 14 twist shooting 168 Sierras and 155 Lapuas, out to five hundred meters but have not tried them past there. In a pair of 13 twist barrels, the 168's are great out to 700 M but a little iffy at 800 and useless at 900. Regards, Bill

Locally, I only have a 300 yd. range available. We are in the mid seventies so temp is not an issue. If I had a longer range available, I would test to find the limitations of the 175. I barreled up another action with a #5 Shilen with a 1-10 twist because I can't wait and show up at school with equipment that will not perform. When looking online it gets confusing as 1/14 generally is used for 150 grain or less, but Berger says some 168's will work, I think I will call Sierra and get their thoughts on this. Glad I found out in time to rebarrel. I might throw that rifle in the truck and if there is any slack time in the course, try to get off a couple of shots at longer range and see what happens. Thanks for the advice! Lee.

I bought a Savage 110 on the cheap many years ago, listed as a "discontinued heavy barrel Target rifle" with no twist listed, basically to shoot 180-210 gr bullets.

After I got it home I checked the twist, 1-14, and plugged it into my twist rate program and ballistics programs to see which weight bullet, velo, etc., would be the best.

"Optimum" twist just means that mathematically there is a twist that is "THEORETICALLY OPTIMAL" at a certain range of bullet lengths and velocities and usually heavier bullets are longer except for RN's.

THIS shooter DIDN'T like anything longer than ~1.15" at ~2700 fs+/-...basically the lighter 100-150 gr bullets from 2600-3000 fs, and the heavier 180-220 gr EXCEPT RN's would yaw, flip, etc. Even 165's, EXCEPT RN's wouldn't quite stabilize... out to ~300-350 yds...the RN's pretty much always did less than 1 MOA... and Hornady 130 gr SP was the most accurate doing bugholes most of the time and that is the bullet that gets shot with this rifle exclusively.

Bottom line...the ONLY way to know for sure is to actually test several bullets at several velo's.

You have to remember that it is BULLET LENGTH and VELOCITY, NOT bullet weight per se, that determines which twist works best.

Luck

One other thought-I've heard many experienced long-range shooters say that marginal twist rates will handle slightly longer bullets in calm conditions but get "twitchy" and go unstable when the wind comes up.

Clarence

I had an interesting discussion with one of the Sierra techs. He was of the opinion that the 175 SMK would be good to go out to 1k. with the 1-14. With the 175 leaving at over 2600 fps it will still be supersonic at 1k. He touched on bullet lengths and I was asking him about the 155 Palma and he said that basically, in length and bc, it was built to closely duplicate the 175, meaning that if I had a stability problem with one, I would have it with the other, EXCEPT that with the higher velocity achievable with the lighter bullet, it might well be a good choice. Interesting stuff, and I am on a steep learning curve. I will take the new rifle for the class just to be safe . I have one of the original box-stock 1965 push feed M-70 sporter that has all the features that everyone loves to hate. My Dad bought it in 65 and I used it to kill my first two deer at 10 yrs of age. I pulled it out of the safe earlier this year when I found a nice original take off barrel in 308, it was originally a 243 which I have too many of. I screwed in the new barrel and it indexed and headspaced perfectly, took it to the range and it was sub 1"/100 and when I shot it with my 175smk/43.5 R15 load, it repeatedly shot 1-3/4" groups at 300. It was going to be my backup rifle for the class, but if the new rifle can't better that, it could be my primary! I do wish I had acess to a longer range though, as I would like to experiment further with the slower twist to see what its limitations will be. Maybe after the class. Thanks to all for the help and any further advice/opinions.

There are several FREE online twist rate programs and Quick Load is an excellent interior/exterior ballistics program that will give you bullet lengths.

You ALSO have to have the actual bullets to compare the boat tails, bearing surface, nose and general profiles, lengths, ogive points as they ALL have considerable effects on actual bullet performance.

Long Range Hunting.com, Sniper forums.com, Snipers Hide, Long Range Only and many other similar forums covering long range shooting specifically are available online which might answer your question more directly as it is MUCH more specialized than general hunting.

I have several "hunting" rifles that CAN and have taken varmints/edible game out at those distances on occasion but they are NOT out-of-the box...I designed and built all of them specifically for long range...INCLUDING THE RELOADING COMPONENTS. If you have one of those one-in-a-million factory rifles with a take off barrel added that shoots bug holes with little or no effort I certainly wouldn't' waste it on targets...except to verify it's actual accuracy...then put it away for hunting only to preserve that barrel AND the brass/bullets/reloading components you used.

I've been at this game a long time and know how difficult it is to get ALL the pieces and parts to come together to make a bugholer that will continually repeat those bugholes...so if you have one, be VERY kind to it.

Luck

I bought over 100 of the barrels . Not all of the received were from the cadet rifles , which had the 1-14 twist . Some were , if I remember , 1-12 or 1-11.5 . The Canadian m82 had a faster twist . Again this is going from memory . The 155 palmas will be the only projectile I've found to stay stabilized at 1000 . That's what it was made for . Bill Smallwood at Norman Clark firearms will have all the info and more .
Good luck , Gary

Nonagonagin, thanks for the advice. That the M-70 may well be a fluke, I have no doubt. Not all take-off barrels are worn out or poor performers, as you well know. Sometimes folks just want a different chambering. I bought five of these barrels from a gunsmith on Ebay and all were in excellent condition, inside and out. I imagine it was just good luck or possibly good quality control, that the new barrel just rolled right in with no mods as it had factory irons that lined right up. No machine work necessary!
I doubt that I will wear it out as I have plenty of hunting rifles and it is way down the list. I have been hitting the range three times a week and it continues to produce sub 2" @ 300 as long as I do my part. It certainly loves the Re15/M118 load. After working through a few bugs on the Mauser/Shilen combo, it is coming around nicely and will be my primary for this class. I pulled the Cadet barrel(1-14) off last night and put it in the lathe to slim down the O.D. a bit as in a H.S stock it is very muzzle heavy.
Gary, Thanks for the info! All five of mine turned out to be 1-14, but they are still excellent performers. Wish I would have gotten one of the faster twist ones in the lot as it would have saved me several hundred dollars on this project. Thanks again guys!

Twist rates, software programs and drop tables are ALL great tools to get us where we want to go. In todays world of techno-babble and instant information many of us forget that the PRACTICAL PART ALSO goes along with the theory part, and the proof of the pudding is EATING IT, not just looking at the recipie...so to speak.

That old saw about the rifle never reading that part about how it's SUPPOSED to act, so it just goes about doing what it WANTS to do.

Luck