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This is an old thread I started last year, but I finally got around to trying to see if I could a little better accuracy from my model 70. I still haven’t started loading but I have all the components & dies. I was able to clean up old grease off of the trigger internals and lighten it up a little, so it’s better than it was, still not great. I bought a new spring & will install that next.
I thought I would go out this afternoon and shoot up some different factory ammo that I have to see what provides the best group. None of it was match ammo, just some hunting ammo. I shot Winchester 95gr extreme point, Hornady 95gr Superperformance SST, and I had a 17yr old box of Winchester 100gr power points that I found in my ammo stash. I shot 3 rounds of the extreme point to get it dialed in and then ended up with a 1.19″ group, shooting off of sandbags, so definitely an improvement. I then shot the Hornady, three rounds to get it dialed in and got a 1.8″ group, so not as good as the extreme point. I then got the old box of 100gr power points and WOW, it shot dead-on, first shot, and I shot a 3 shot group at .297″ with the first 2 basically in the same hole and the 3rd touching the others. I was expecting my worst group from the 100gr because I thought that the model 70 had a 1 in 10 twist rate and I had read that it didn’t handle 100gr very well. I’m wondering if this rifle has a 1 in 8 twist rate? I’m not sure how to tell or if any of them came with a 1/8 twist in those days. Anyway, I have plenty of brass now & will start my reloading experiments (finally) and see if I can work some loads that can come close to that inexpensive, 100gr power point factory ammo.
Jerry
I'm more of a shooter than a collector, but I do have a few collectibles.
Philippians 1:6
November 7, 2015
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Nice shooting from a fine old rifle! Personally I don’t put much stock in a three shot group, many rifles not capable of an MOA five or 10 shot group can manage a misleading three shot group. OTOH, MOA accuracy is not necessary for most hunting situations but it sure makes loading for and shooting these old Winchesters fun! Good luck on your reloading project, looks like your rifle will be able to take advantage of a good load when you find it.
Mike
For 100 grain bullets of normal length, a 1 in 10 twist is more than adequate. In fact, a number of shooter/handloaders who owned Remington Model 722 rifles chambered in .244 Remington with 1 in 12 twists found their rifles shot 100 grain bullets very well, historical bushwa to the contrary notwithstanding.
The current 6mm fashion for ultra long bullets that demand a faster twist rate ignores the experience and expertise of the developers of the American 6mm twins, most particularly the late Warren Page, a leading light of the benchrest movement and an accuracy expert of the first water. His .240 Page Pooper and Super Pooper were wildcat antecedents of the .243 Winchester and .244 Remington.
If you are shooting a Pre64 Model 70 with its original .243 WCF barrel, just stay with projectiles of historically conventional length to weight ratios and you can shoot impressively small groups, given some attention to handloading details. There are some stability predictor engines online that can help with bullet selection. You plug in weight, length, style and velocity, density altitude. It predicts a stable to wobbly index number and color. Green is good, yellow is maybe, red is sideways. There is one at https://www.jbmballistics.com and another at https://bergerbullets.com.
You have in your hands a prairie dog and woodchuck death ray.
As Clarence has said, before I modified the bedding on a standard Model 70, I’d see what reducing and increasing the barrel tension forearm screw a couple of turns might do to alter group size. Conventional wisdom for some time has been free floating the barrel is usually — emphasis on USUALLY — a better idea, but it is diffiicult to do without uglifying the rifle. Yes, you could afterwards glass bed it, but before doing those things I’d take a deep breath and recall that, among the old guys calling the shots at Winchester before The Dream Team from Ford came in to screw things up, were some veteran, serious target competition shooters. Dave Carlson and Tom Henshaw not least among them. It was on their (and their like-minded predecessors’) watch, and with the advice of accuracy minded experts like Col. Whelen, that mechanically adjustable bedding tension was built into the Model 70. They were not novices in the sport and, unless you have an interest in competitive target shooting (in which current business vintage rifles have no place), I’d devote a fair amount of time adjusting barrel tension and shooting before doing anything else. At least according to one of its most ardent admirers, the late Jack O’Connor thought a Model 70 hunting rifle – whether out of the factory box or from the bench of the best custom gunsmiths like Al Biesen, Len Brownell, et al. — was doing well to shoot 1.25 to 1.5 inch, 5-shot groups at 100 yards. Occasionally, he wrote, when his “wibbles” compensated for his “wobbles”, they might do better but their average accuracy was more than enough for what he considered ethical long range shots at game. And he was a triple Grand Slam sheep hunter.
Like you, I really enjoy the old Model 70 rifles. I admire them but I like shooting them a lot more and I expect your’re the same.
- Bill
WACA # 65205; life member, NRA; member, TGCA; member, TSRA; amateur preservationist
"I have seen wicked men and fools, a great many of both, and I believe they both get paid in the end, but the fools first." -- David Balfour, narrator and protagonist of the novel, Kidnapped, by Robert Louis Stevenson.
Jerry, sorry to hear about the Hornady SST bullets. That is what I just loaded in my 6mm Lee Navy. I wanted a flat base because of the style of rifling in the Lee barrel. When you get into reloading take a look at what the bench rest guys are loading for their 6 mm’s. The 105 Bergers are real popular.
Chuck said
Jerry, sorry to hear about the Hornady SST bullets. That is what I just loaded in my 6mm Lee Navy. I wanted a flat base because of the style of rifling in the Lee barrel. When you get into reloading take a look at what the bench rest guys are loading for their 6 mm’s. The 105 Bergers are real popular.
Chuck, I’m not sure which 105 Berger you mean, but I tried all of Berger’s various 105gr bullets on their stability calculator, plugging in a 1-10 twist rate and using 2950 for the velocity. The projections came up red/unstable for all of them, with a prompt that said I needed a twist rate at least as tight as 1-8. I’ve illustrated the Target 105 boattail but the other versions produced the same result.
For what it’s worth, Jerry might want to run his disappointing SST load across the JBM version of this calculator, which offers to project stability for a broader variety of bullets, even those that are fictional. Granted it’s just projections but it’s free and high-end bullets are anything but. As a matter of cost, projecting stability would seem to be a good starting place if we’re trying to screen for the best 6mm accuracy load given a 1-10 barrel. 
- Bill
WACA # 65205; life member, NRA; member, TGCA; member, TSRA; amateur preservationist
"I have seen wicked men and fools, a great many of both, and I believe they both get paid in the end, but the fools first." -- David Balfour, narrator and protagonist of the novel, Kidnapped, by Robert Louis Stevenson.
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