375 Caliber A-max...might be a possibility. Please read.

[montana_native]

Following Beng's use of sd's to make a ball park estimate of max theoretical bc's for a given bullet weight and diameter, it should not be difficult to construct a 300ish grain .375 bullet that would achieve mid to high .6 g1 bc's. If that proves out, the .375's might do a bit better yet than the above numbers indicate.

However it all shakes out, I sure would like to have some better .375 bullets to shoot. I hope somebody will see their way clear to make that happen and I would like to help out however I can.

I will continue to correspond with Hornady and the information in this thread is very valuable so far. I will read through it all in about a week, condense and summarize then relay to Hornady. I will also provide them with links to the threads I've started on other sites.

Keep the information flowing.

 

[Erik Kiser]

There's already bullets for the 375 caliber in the 260-300 grain range. There is nothing in the 350 range. It's gonna take a 350 grain bullet to compete with the 300 gr 338's. I think a lot of guys are like me, they'll keep their 338 variants if the bullet manufacturers put out another 300 gr 375 bullet. Put out a good 340-360 gr 375 bullet and you'll see a lot of guys, myself included, make the leap to the bigger caliber. I personally want to see Berger do it but hats off to Hornady if they get there first. Whoever does it will sell all they can produce

 

[montana_native]

Please let me know what information you would like to see in a poll or polls and I will send Len an email to get them started.

Thanks!

 

[Michael Eichele]

Equal nose profiles, boat tail dimensions, diameters and weights, bullets that have a lower specific gravity such as copper will always have a lower BC. These will require a longer body and subsequent bearing surface to match the weight if a jacketed lead bullet. Longer bullets for a give form create more drag, period. If you make them in identical dimensions, the all copper bullets will be lighter and subsequently have less sectional density and you guessed it, a lower BC. Either way, jacketed lead will always have more potential. Then the twist becomes an issue. Imagine creating a mono metal the was to compete with the 215 vld or 230 OTM. What kind of length would they have. Twist? Well a 10x won't work. How about reduced velocity with a longer bearing surface? Copper bullets have their strengths and a place but will always have less of an advantage over jacketed lead.

 

[benchracer]

Equal nose profiles, boat tail dimensions, diameters and weights, bullets that have a lower specific gravity such as copper will always have a lower BC. These will require a longer body and subsequent bearing surface to match the weight if a jacketed lead bullet. Longer bullets for a give form create more drag, period. If you make them in identical dimensions, the all copper bullets will be lighter and subsequently have less sectional density and you guessed it, a lower BC. Either way, jacketed lead will always have more potential. Then the twist becomes an issue. Imagine creating a mono metal the was to compete with the 215 vld or 230 OTM. What kind of length would they have. Twist? Well a 10x won't work. How about reduced velocity with a longer bearing surface? Copper bullets have their strengths and a place but will always have less of an advantage over jacketed lead.

This is consistent with my meager understanding of these things. It is why I had thought it possible to construct a lead core bullet of similar weight and a higher bc than the CE MTH's. I don't know if I am right about that or not. Someone does, though, and that is where the engineers come in...

 

[MontanaRifleman]

Equal nose profiles, boat tail dimensions, diameters and weights, bullets that have a lower specific gravity such as copper will always have a lower BC. These will require a longer body and subsequent bearing surface to match the weight if a jacketed lead bullet. Longer bullets for a give form create more drag, period. If you make them in identical dimensions, the all copper bullets will be lighter and subsequently have less sectional density and you guessed it, a lower BC. Either way, jacketed lead will always have more potential. Then the twist becomes an issue. Imagine creating a mono metal the was to compete with the 215 vld or 230 OTM. What kind of length would they have. Twist? Well a 10x won't work. How about reduced velocity with a longer bearing surface? Copper bullets have their strengths and a place but will always have less of an advantage over jacketed lead.

The jacketed lead core bullets have the SD and form factor advantage over the mono's up to .308 cal or so. Once you start getting into larger diameters it becomes more challenging to build jacketed lead core bullets with good form factors. Joel Russo went out and shot 300 gr SMK's against 300 gr CEB's, same velocity, and the CEB's shot flatter. However he reported the jacketed bullets were more accurate.

Kiwi Greg shot 425 gr 375 cal CEB's to out past 2000 yds and reported a BC of about 1 based on required come ups and had good accuracy with them. You will never see a 375 cal 425 gr jacketed lead core bullet with a BC of 1 because the form factor can not be attained. It might be possible in a more rigid metal or alloy like tungsten but then you loose the expansion factor for a hunting bullet.

The only reason I would buy a standard cartridge 375 such as a Ruger or RUM, etc, would be for large dangerous game in Africa or big bears in Alaska. I do not consider them a long range cartridge in the way I consider a 300 RUM or 338 EDGE to be LR cartridges. The 375's don't compete with these IMO. I would consider a 375 CheyTac and if I ever built one it would have a gain twist to about 7.5" to shoot long heavy high BC mono's in the 1 BC class.

Now I know a few of you see things a little differently with the standard 375's but there are a lot of guys who think the same as I do. As long as there are the big 338's, I see no reason to get a 375 that shoots lesser BC bullets at lesser velocities. If I did get one, it would be a 375 LM Imp and I would shoot 350 CEB's through it with the appropriate twist barrel. They would go faster and have a higher BC than the 350 SMK or similar bullet.

 

[Michael Eichele]

Kiwi Greg shot 425 gr 375 cal CEB's to out past 2000 yds and reported a BC of about 1 based on required come ups and had good accuracy with them. You will never see a 375 cal 425 gr jacketed lead core bullet with a BC of 1 because the form factor can not be attained.

That's my point. If you were to make a jacketed lead bullet of equal dimensions to the 425 grain copper bullet, you would be gaining weight and sectional density and again, better BC. If I'm doing the math right, the leaded version would weigh a bit over 500 grains. More recoil yes but ALOT more impact energy.

 

[montana_native]

I think this is getting off topic a little bit and hopefully it won't turn into a huge debate...

When I began discussion with Hornady, it wasn't under the presumption that they could create a bullet to compete with the turned solids with regard to ballistic coefficient, terminal performance, exterior ballistics, etc. What would make me happy is a bullet that can compete with the 350 SMK price point (i.e. under $1.00 each) but offer a more advanced design than the SMK. I can only confirm the 350 SMK G1 BC to ~ 0.725 rather than their advertised 0.805 number. I've sent over 500 of them downrange at 2985 fps at 5515'. My 338 Lapua with a 300 Hybrid at 2805 fps outperforms it and remains supersonic for 150 more yards with less drift. Which rifle do you think gets fired more?

It seems to me that Hornady (or anyone else hint: BERGER!!!!) could create a 350 grain class bullet to outperform the 300 grain Berger while keeping cost down AND perform well on game.

Additionally, when shopping for 375 caliber barrels, many of the manufacturers I spoke with didn't care to build 375 caliber barrels for the long range crowd. Many of them stated that they wanted bullet manufacturers to make up their mind on the solid vs. jacketed lead core design so the barrels could be cut accordingly.

 

[MontanaRifleman]

That's my point. If you were to make a jacketed lead bullet of equal dimensions to the 425 grain copper bullet, you would be gaining weight and sectional density and again, better BC. If I'm doing the math right, the leaded version would weigh a bit over 500 grains. More recoil yes but ALOT more impact energy.

Yes you would, but I don't think it would be possible to make a 375 jacketed lead bullet with the same form factor as a mono in the 1 BC class. I think the 350 SMK is about as good as gets with 375 cal jacketed lead bullets... maybe a little better. Just guessing here, but the increased ratio of lead to jacket would cause a compromise of the integrity of the bullet.

 

[Lefty7mmstw]

The only reason I would buy a standard cartridge 375 such as a Ruger or RUM, etc, would be for large dangerous game in Africa or big bears in Alaska. I do not consider them a long range cartridge in the way I consider a 300 RUM or 338 EDGE to be LR cartridges. The 375's don't compete with these IMO. I would consider a 375 CheyTac and if I ever built one it would have a gain twist to about 7.5" to shoot long heavy high BC mono's in the 1 BC class.

Now I know a few of you see things a little differently with the standard 375's but there are a lot of guys who think the same as I do. As long as there are the big 338's, I see no reason to get a 375 that shoots lesser BC bullets at lesser velocities. If I did get one, it would be a 375 LM Imp and I would shoot 350 CEB's through it with the appropriate twist barrel. They would go faster and have a higher BC than the 350 SMK or similar bullet.

That is why some of us are talking two different bullet weights. One to optimize existing cals like the 375h@h and rum, and a heavier weight to really make the bore diameter shine with 378 wby and above. The 375 cal has enough frontal area that Taylor KO factor nearly has more meaning than energy assuming the bullet can be engineered to actually expand at all useful ranges, so I am not as concerned about energy as the ability to flatten trajectory to a usable arc. If I can put two holes through a deer or elk with one bullet that will be sufficient.

A bullet like the disconinued barnes mrx could be engineered with a poly or aluminum tip over a gaping cavity (to ensure expansion) but enough "junk in the trunk" to actually have enough weight to act like a standard lead core momentum and density wise. Make it a bore rider to drop pressures and be able to get a real head of steam on it.

 

[Erik Kiser]

I said earlier that at equal weights the mono has the advantage. I don't think that's even up for debate. I do think that a company like Berger could build a 350-360 gr lead core bullet that would beat or match the SMK in bc and be suitable for hunting small to medium game. If Hornady beats them to it then hats off to them. I also think that if you can't beat or match the 300 gr 338 bullets in bc for a dollar or less then your wasting your time

 

[Michael Eichele]

It's very debatable. Equal weight between the two means the mono metal will be longer. Adding length does a BC no favors. In fact just the opposite. The only time length aids in BC is lengthening the nose and or boat tail.

Same SD, same form factor, longer projectile = lower BC.
Same SD, same form factor, shorter projectile = higher BC.

When dealing with lighter for caliber bullets, mono metals maybe easier to make longer noses without making a ridiculously short bearing surface but in the context here, using heavier for caliber bullets (this is about long range) there is not a nose profile you can put on a mono metal that you cant put on jacketed lead bullet.

I have personally shot the 178 amax over double chronographs side by side with the 177 GS bullets. Lets just say that the GS bullet wasn't even close to published. In fact, they were about the same as the 178s. By looking at them you would think that they would blow the 178s doors off but it just isn't in the cards.

You cannot fight sectional density and specific gravity. They just flat out play too big of a role in what makes a BC.

 

[Erik Kiser]

So you're saying if you had a sleek, aggressive design, high bc mono at a given weight, lets say 300 gr, that you could build a lead core bullet that could match it or beat it at the same weight? If that's the case I have a lot to learn about bullet design

 

[Michael Eichele]

You might be able to get away with it with light for caliber bullets such as a 300 grain .375 cal bullet but its not going to be as much as you think. About 10%. While form factor is important, sectional density is a much larger peice of the pie. The limiting factor here is the bearing surface of the jacketed lead version. That said why limit yourself to a 300 grain bullet in this caliber? A 300 grain .375 bullet will never match that of a 300 grain .338 bullet be it a mono metal or jacketed lead. Using a 300 grain bullet in a .375 is kind of like using a 180 in a 300 magnum. If you need to use a 180 grain for long range hunting, Its time to go 7mm. If you get things up into the 350 grain, the .375 starts to become beneficial. At this point, if you make a mono metal with the same weight and profile of the lead core, the mono metal will be longer with more drag and require a tighter twist. In my mind, mono metals aren't advantageous unless you're looking for durability which sometimes I do. Exterior ballistics are another story.

I see your point and won't say you're wrong. We both have to remember that there are limitation to both and I'm seeing things from my point of view and you're seeing it from your point of view. I won't say either of us is wrong, just that both types have their upper and lower limits. But I dare you to compare side by side the 178 amax against the 177 GS mono metal. The results might shock you.

M