Okay so what you're saying, that saami chamber is basically zero freebore chamber, with longer throat than normal due to less leade andle?You're confusing the length of the lead for the freebore
Okay so what you're saying, that saami chamber is basically zero freebore chamber, with longer throat than normal due to less leade andle?You're confusing the length of the lead for the freebore
Here's an image of the 6.5 PRC SAAMI spec reamer, it sure has more than 0.016 of freebore. The lead length is 0.016 and the freebore is 0.205 according to that print.The freebore is only 0.019, it does have slightly longer lead than normal as the andle is 1° vs 1.5°. The case has a long neck for 270 at 0.329 but you'll want more FB for a 170 Berger, as the bearing is 0.407, the neck helps you out way more than the freebore does. Freebore is the length after case mouth that's 277 diameter. Where the taper starts to the lands, usually indicated by a 1.X 30' measurement that's the start of the lead.
No. What I'm saying is you're confusing the lead length (0.019) for the freebore. The freebore would be measured by subtracting the case length plus the lead length (2.619) from the 2.7718 dimension. That gives you 0.159 freebore. Some people add the length of the lead plus the freebore, so essentially it gives you 0.178 of freebore. That's a good bit and plenty for the 170 EOL.Okay so what you're saying, that saami chamber is basically zero freebore chamber, with longer throat than normal due to less leade andle?
No. What I'm saying is you're confusing the lead length (0.019) for the freebore. The freebore would be measured by subtracting the case length plus the lead length (2.619) from the 2.7718 dimension. That gives you 0.159 freebore. Some people add the length of the lead plus the freebore, so essentially it gives you 0.178 of freebore. That's a good bit and plenty for the 170 EOL.
It has .188 freebore and .16 lead.View attachment 170122
Here's an image of the 6.5 PRC SAAMI spec reamer, it sure has more than 0.016 of freebore. The lead length is 0.016 and the freebore is 0.205 according to that print.
You're right. I had a major brain fart. Good thing it has a long neck. If I were to build a custom I would definitely throat it to have 0.150 Freebore or so. Sorry for the back and forth, I was completely overlooking the dimensions.Freebore stops where the chamber is no longer 0.278 diameter(2.619 on print) , at that point the lead/throat starts which tapers from 278 to 270 at 2.771". The bearing surface of the bullet is 277 diameter. That will only go into the throat maybe 30-40 thousandths before it engages the lands. Any more than that you're jammed. This chamber has nothing close to 178 freebore. Freebore is usually 1 thou larger than bullet diameter. This chamber has essentially no freebore.
Yeah it's 0.188 Freebore technically. I just added the length of the lead to the freebore. You're right, but I just add the two together because that's really how much bearing surface can be outside of the neck before engaging the rifling. Tonight has not been my night for studying reamer prints hahaIt has .188 freebore and .16 lead.
Belts are useless in today's rifles. They may have been used in the Dark Ages to headspace the round, but they are just superfluous remnants of ancient design in these modern times. I was a member of one site years ago that had a member whom machined-off the belt on his .300 Weatherby cases. As both a machinist and a rifle builder, he had to know that what he was doing would not be detrimental toward the performance upon the target of the end product.… … without the belt.
You may have liked my .358 Sierra Stomper. It was exactly what the .35 Whelen would have been had the Whelen had been formed on a .532" case. It was pure punishment to fire it. The recoil in a nine-pound rifle was vicious. It produced 4092 foot-pounds of muzzle energy behind a 250-grain bullet at 2715 fps. I was good with it for about a dozen rounds. After that many, I got so flinchy that I just couldn't fire it any more for the day. It was accurate, producing 3/4" groups at 100 yards with 60.0 grains of IMR-4320 and that 250-grain bullet. I built the rifle just to see if I could attain 4000 foot-pounds of muzzle energy. I did, in fact, mightily succeed...Presently have a 35 Whelen .. .. ..