Pre '64 M70 in .30-'06

[Marlin Junky]

Did Veral specifically recommend Blue Soft for your HV experiments?

I've used LBT Soft Blue before as well as BAC and a host of other personal concoctions to get my boolits going as fast as their respective guns allowed while still maintaining accuracy. Yes, LBT Soft Blue is probably Veral's favorite.

MJ

[Marlin Junky]

Not sure what you mean about "tough enough". I shoot the 311466 with the same accuracy at the same velocity in both the .308W and the '06 as I did with the LBT bullet. Perhaps the "not knowing" and assumption is simply not having tested it?

Larry,

I'm surprised you don't understand tough as it applies to cast boolits. That may be clouding your judgment with respect to this RPM thing. Tough would be the ability to withstand torque... torque involved with respect to interior ballistics. Sorry, I just can't get behind your exterior ballistic RPM thing; therefore, let's return to the subject and forget about stuff we can't unequivocally prove or refute. The one statement I can confidently make is that if a boolit doesn't leave the barrel in balanced condition, it's not going to shoot accurately no matter what its RPM.

MJ

[Larry Gibson]

MJ

I mistakenly thought you were still discussing cast bullet design. I am thoroughly aware of what "tough" means with relation to alloys.

It's not my ballistic RPM thing. The adverse affect of RPM on unbalanced bullets, cast or jacketed has been well known for many years regarding exterior ballistics. Reading the articals in most reloading manuals will give you some idea.

Sorry to have taken up your time.

Larry Gibson

[Marlin Junky]

MJ

I mistakenly thought you were still discussing cast bullet design.

Larry Gibson

I am talking about boolit design; i.e., the LBT design is less prone to stripping the rifling than 311466 because of the former's long, solid, groove diameter forward section. 311466's forward section (which initially engraves the rifling) is weakened by grease grooves. 311466's second flaw is that its nose doesn't transition smoothly into its bearing surface.

MJ

P.S. Feel free to PM me links to these articles you speak of since I'm too cheep to purchase new reloading manuals; however, as you stated above, perhaps "unbalanced" is the key. Perhaps we should be more concerned about boolits leaving the muzzle in an unbalanced fashion than over spinning them in flight. Of course, this doesn't preclude the negative affects of too fast a twist with respect to internal ballistics.

[Larry Gibson]

MJ

Looks can be deceiving; if you look close you will notice 3 lube grroves on the LBT bullet and 6 lube grooves on the 311466 (includes the lubed groove in front of the GC). The depth of those lube grooves is actully deeper on the LBT but it all depends on how much ech is sized. However, look close at the width of the 2 forward grooves on the LBT bullet; they are a tudge over twice as wide as the 311466 grooves which are all the same width. Now if you measure and do the math you will see that the actuall surface area of the lube grooves is the same. The surface area of both bullets is close to identical. The scraper groove of the 311466 was a concern of mine as a potential weakness also. I would prefer it wasn't there. However, actuall shooing results do not verify it as a weakness. I know all of this because i went through it all when Bass and I were shooting the LBT bullet in the '06 (I was shooting it in 2 '06s with 10" twists). Now I'm just saying they are both equally good bullets and am not trying what so ever to dissuade from the LBT bullet. I would have it, as I've said, if I didn't already have two 311466 moulds. The LBT bullet is a very good choice for what you want to do. But then what the heck do I know anyway, after all you haven't shot either one and are still theorizing about them and I have, in fact, shot both bullets with acceptable accuracy in 2 different '06s up to 2500 fps.

PM you links to Hornady, Speer and Sierra's reloading manuals? But, uh, excuse me but they sell those to make money and don't post them on the internet. I've seen them in used book stores for a reasonable price. Seems to me if you want to dance you might want to consider paying the band.

All bullets coming out of barrels are "unbalanced" to a degree or other, some more so than others. This is why we shot groups instead of all bullets going into one hole. Weare concerned about having the bullets as balanced as possible when they leave the barrel. This is why we size bullets, fit them to the throat, weight sort them, visual inspect for the slightest defect, ensure GCs are square on the base, fire form cases, Use than appropriate alloy, use an appropriate design, ensure concentricity of chamber case and bore, use slower burning powders to achieve a slower time pressure curve during accelleration, etc, etc, etc, add nauseum. However, what we need to understand is we can drive a cast bullet in a fast twist with as little damage to it from a fast twist as a slower twist if the things mentioned are correct. Both bullets may come out of the barrel at the same velocity with the same imbalance. It is then during the external ballistic phase that the higher RPM of the bullet coming out of the faster twist (remember; same velocity) with have more adverse affect on those imbalances.

A good and dramatic example is why thin skinned explosive varmint bullets spin apart right out of the barrel in fast twist .223s of 7 - 9" twists and they don't in 12 & 14" twist barrels with equal velocities over 2900 fps? The answer is the centrafugal force of the higher RPM exceeds the structural strength of the jacket and the lead. With cast bullets, at a certain RPM level, the centrafugal force begins to over come the rotaional stability of the bullet. This is not to say the bullet is not stabile as in flying point forward, it is. What happens is the bullet begins to gradually spiral outward from it's line of flight. The longer the range the larger the spiral. This is different than the linear dispersion of groups BTW.

Now back to your 10" twist '06 and your choice of bullet; by all means get the LBT bullet. It is indeed a good one and if, that's a pretty big "if" BTW, you do everything else right you might get respectable and consistent accuracy at 2500+ fps out of your 10" twist '06. If it was easy everyone would be doing it and we wouldn't be having this conversation, would we

Larry Gibson

[geargnasher]

Wow. I figure a seven twist at 2900 to be just shy of 300,000 rpm, or a hair less than 5,000 rotations per second. that's many times faster than a dental drill. Everything has its limits.

Gear

[Marlin Junky]

MJ

Looks can be deceiving; if you look close you will notice 3 lube grroves on the LBT bullet and 6 lube grooves on the 311466 (includes the lubed groove in front of the GC). The depth of those lube grooves is actully deeper on the LBT but it all depends on how much ech is sized. However, look close at the width of the 2 forward grooves on the LBT bullet; they are a tudge over twice as wide as the 311466 grooves which are all the same width. Now if you measure and do the math you will see that the actuall surface area of the lube grooves is the same. The surface area of both bullets is close to identical. The scraper groove of the 311466 was a concern of mine as a potential weakness also. I would prefer it wasn't there. However, actuall shooing results do not verify it as a weakness. I know all of this because i went through it all when Bass and I were shooting the LBT bullet in the '06 (I was shooting it in 2 '06s with 10" twists). Now I'm just saying they are both equally good bullets and am not trying what so ever to dissuade from the LBT bullet. I would have it, as I've said, if I didn't already have two 311466 moulds. The LBT bullet is a very good choice for what you want to do. But then what the heck do I know anyway, after all you haven't shot either one and are still theorizing about them and I have

I own an LBT 310-180-LFN and I know something about how it shoots compared to the conventional designs by RCBS, SAECO and Lyman

in fact, shot both bullets with acceptable accuracy in 2 different '06s up to 2500 fps.

PM you links to Hornady, Speer and Sierra's reloading manuals? But, uh, excuse me but they sell those to make money and don't post them on the internet. I've seen them in used book stores for a reasonable price. Seems to me if you want to dance you might want to consider paying the band.

All bullets coming out of barrels are "unbalanced" to a degree or other, some more so than others. This is why we shot groups instead of all bullets going into one hole. Weare concerned about having the bullets as balanced as possible when they leave the barrel. This is why we size bullets, fit them to the throat, weight sort them, visual inspect for the slightest defect, ensure GCs are square on the base, fire form cases, Use than appropriate alloy, use an appropriate design, ensure concentricity of chamber case and bore, use slower burning powders to achieve a slower time pressure curve during accelleration, etc, etc, etc, add nauseum. However, what we need to understand is we can drive a cast bullet in a fast twist with as little damage to it from a fast twist as a slower twist if the things mentioned are correct. Both bullets may come out of the barrel at the same velocity with the same imbalance. It is then during the external ballistic phase that the higher RPM of the bullet coming out of the faster twist (remember; same velocity) with have more adverse affect on those imbalances.

A good and dramatic example is why thin skinned explosive varmint bullets spin apart right out of the barrel in fast twist .223s of 7 - 9" twists and they don't in 12 & 14" twist barrels with equal velocities over 2900 fps? The answer is the centrafugal force of the higher RPM exceeds the structural strength of the jacket and the lead

Yeah, the angular components of acceleration within the barrel probably fractures the bullet jacket at the land/groove interface. It sounds like you're inferring that RPM alone is responsible for the bullet's structural failure. From that it would follow that a bullet simply spinning in place, at a high enough RPM, with no other influences, would "spin apart" which would be impossible without experiencing serious distortion first (probably shrinking in length with a proportional expansion in diameter before blowing apart). How many RPMs would that require?

With cast bullets, at a certain RPM level, the centrafugal force begins to over come the rotaional stability of the bullet. This is not to say the bullet is not stabile as in flying point forward, it is. What happens is the bullet begins to gradually spiral outward from it's line of flight. The longer the range the larger the spiral. This is different than the linear dispersion of groups BTW.

Now back to your 10" twist '06 and your choice of bullet; by all means get the LBT bullet. It is indeed a good one and if, that's a pretty big "if" BTW, you do everything else right you might get respectable and consistent accuracy at 2500+ fps out of your 10" twist '06. If it was easy everyone would be doing it and we wouldn't be having this conversation, would we

Larry Gibson

BTW, I've obtained very good accuracy from a 1:10" 30-30 at 2400+ fps and that's definitely at over 40K PSI (179 grain LFN at 29 BHN). If I can't beat that performance by a considerable margin with the much larger '06 case and a somewhat lighter boolit, it won't be due to my perfect little boolits spinning too fast in air... unless of course I can retrieve 'em after they've expended in air two miles down range and they look more like round balls than boolits.

Anyway, this was not the direction I had intended for this thread to take, so I'll have to say, no more for me, thanks.

MJ

[Larry Gibson]

MJ

The same bullets shoot very well below 2900 fps in the same barrels with the rifling that would cause the same distortion to the jackets. A rough bore does cause them to fly apart at a lower velocity RPM from the faste 7 - 9" twists. The same bullets shoot very well in 12 and 14" twists with the same rifling at much higher velcocity. It takes 300,000 RPM, give or take, as Gear mentioned. Try a 55 gr SX, 50 gr Blitz, Speer 52 HP or Hornet bullets at 3200 fps out of a 7 (329,000 RPM) or 9" twist .223 and what the grey puff of smoke between 25 and 50 yards to the target. Also note no bullet holes in the target. All three bullet makers, Hornady, Sierra and Speer caution against using these bullets for the very reason mentioned. I have watched this happen on numerous occasions. It also can happen with lighter varmint bullets in the 6.5 Swede when they are pushed to 3200+ fps. The Speer 110 gr FPHP also can come apart above 3000 fps in 10" twist .30 cals. You won't find a higher velocity load for it than the mid 2900s in Speer's manual #14.

The bullet "spinning in air" has nothing to dow ith it. It is simply the higher spinning that cases it. The information of this is readily available. I also am done on this thread. Good luck with your '06 and that LBT bullet but you will find that the contents of this conversation are very important for the direction you are headed.

Larry Gibson

[Marlin Junky]

The bullet "spinning in air" has nothing to do with it.
Larry Gibson

Larry!... so you agree the RPM theory, or threshold theory (whatever) is not an external ballistic phenomenon... that makes me very happy! Therefore, there's nothing left to argue about and we can move on to Pre '64 '06 type stuff.

MJ

[rockrat]

Have you looked at the RCBS 30-165 Sil?

[Char-Gar]

I have a very nice 1954 vintage Winchester 70 in 30-06. It is a nice rifle, but doesn't work any different from most other 30-06s. I use the same bullets (311467, 311407, 311291, 311284, and RCBS 165 Sil.) with the same charges and same results.

I am not into spitzer cast bullet nor high velocity cast bullets, so I will let others sort that out.

[Marlin Junky]

Have you looked at the RCBS 30-165 Sil?

I have that mold but I need more groove diameter bearing surface for HV. Also, this chamber, while it has a short throat, is very wide in the neck area... .303 British-like wide. I'm able to seat a .3125"-.3130" boolit into either FC or LC brass and chamber the round without scuffing brass in the neck area.

MJ

[Marlin Junky]

I have a very nice 1954 vintage Winchester 70 in 30-06. It is a nice rifle, but doesn't work any different from most other 30-06s. I use the same bullets (311467, 311407, 311291, 311284, and RCBS 165 Sil.) with the same charges and same results.

I am not into spitzer cast bullet nor high velocity cast bullets, so I will let others sort that out.

Chargar,

The serial number on mine starts with 222, so I guess that makes your M70 and mine about the same age.

MJ

[geargnasher]

I have that mold but I need more groove diameter bearing surface for HV. Also, this chamber, while it has a short throat, is very wide in the neck area... .303 British-like wide. I'm able to seat a .3125"-.3130" boolit into either FC or LC brass and chamber the round without scuffing brass in the neck area.

MJ

Have you attempted "HV" with the RCBS silhouette boolit and failed?

Have you done an impact slug or cast of the chamber and throat?

Gear

[Larry Gibson]

MJ

If you're interested regards your rifles short neck and bullets that fit, but if not then ignore. I shot this group today with the new 311466U bullets. I was not getting consistent accuracy over 2300 fps with the 311466 mould as it drops it's bullets at .314 and I size them to .311. In the .308W case the bullets base sticks quite a bit below the case neck with the front driving band just at the leade. With the new 311466U I can size the front 2 driving bands to .300 and form a short meck. The with the 3rd full size (.3105) driving band at the leade the GC is right at the bottom of the neck. Makes for a very short bore riding nose. The question was; will the bullet shoot that way accurately at 2500 fps?

The target below was shot at 100 yards The 1st 2 sighters out of the cean barrel are marked and then I fired 10 shots for record. The first 5 shots went into 1.35". There are 6 shots in that ragged horizontal hole. The 10 shots for record are in 1.45". The start screen of the M35P was at 15' and the recorded velocty is 2517 fps, call it 2530 fps at the muzzle. That's what I'm currently doing at 2500+ fps with a cast bullet. Perhaps you'll better it

Good luck.

Larry Gibson

[PWS]

Hi there,

I'm mostly a lurker and hang out on AccReloading a bit. I am looking for a practice load for my wife's '06 and was thinking a 140-160gr cast at 2400fps would be perfect (kinda like Whelen's 200yd target loads).

Did you get your LBT spitzer and give it a whirl?