Sound Decisions

[Squatch]

Something I hadn't really thought about too much till recently was the speed of sound and the sound barrier when reloading. For our purposes we can use 1,125 FPS as the sound barrier.

As many know I've spent sometime working on light low recoil accurate loads for my big bore rifles. 44 mag and 45/70. When I go back and review the chrono data and compare it with targets I've found that the stuff that has worked well either stays under the threshold or is hot enough to still be supersonic when it hits the target downrange.

Some of my loads have been pretty good but always had a couple of weird acting rounds. These seem to be dancing in the neighborhood of the sound barrier. I'll bet that has been the issue with the occasional flyers. The shock wave can do weird things to bullets. Especially if they go back to subsonic before arriving at the target. That wall can cause bullet to get real unstable.

Is anyone paying much attention to this when hand loading for their Henry's?

I think from now on I will be! I'll either stay under 1,100fps or be high enough above it that the bullet stays there down range at the distances I shoot..

Hand loading is like some other stuff. The more you learn the more you realize what you don't know!

[Cofisher]

I have shot only factory loads so far. When I start to reload, I will keep this in mind. Thank you for the heads up.

[JEBar]

Hand loading is like some other stuff. The more you learn the more you realize what you don't know!

there is no doubt, that is the absolute truth .... with factory loads, there isn't any thinking they either work for us or they don't ..... I know that with reloading I'm prone to over think the process .... I've found loads I'm really happy with for all of the rifles and handguns that I've owned for more than a couple of years .... yet, somehow, I can't seem to leave well enough alone .... I'd love to have the money I've spent trying different powder and bullets that simply didn't work out .... when I buy a can of powder, I write the date on it with a permanent marker .... I have no idea how many different cans I have with dates going back to 1996 .... I have bought boxes of different brands of bullets with a wide range of designs .... I've loaded a few rounds, tested them and put the powder and bullets up on a shelf ....

[CT_Shooter]

That's a really good point, Squatch. The supersonic "wall" that follows a bullet could very well be a factor in its accuracy.

I usually reload 158 grain JHP bullets for .357 magnum with H110 charges that I can use in either my revolver and my rifle. Hornady's ninth documents that charge at 1550 fps from a 16" rifle barrel and 1100 from an 8" revolver. In my case, the Henry would be a bit faster than that and my revolver would be a bit slower. So far, I've only shot the revolver at 25' to 50' and the rifle at 75', so it has not actually been an issue that I can detect; but I would expect at longer distances, the margins of supersonic fps would be a factor.

[RanchRoper]

Learned something new today, thank you.

[Ojaileveraction]

Muzzle velocity is one factor but bullet design is another.
I have been working on a comfortable load my 45-70 to shoot 500yrd silhouettes for some months now. I haven't been able to do it with flat nose bullets. At 500 yrds they'll be all around the target high, low, right, left, or just fall out of the sky around 300yrds.
Now the Black Powder Cartridge shooters can do that all day long with their Sharps and Springfields. They don't use flat nose bullets.
Of course with a lever gun we have more than Ballistic Coefficient to think about when it come to bullet design.
Besides the the possibility of detonating, Tubular mags don't like bullets that are to long and even if you can chamber one at a time will they extract without getting caught up in the works if not fired.
I've had both this issue with trying to shoot a bolt action 30-30 out to 500 meters. The 30-30 is not a 500 meter rifle, not in my hands.

I'd like to add that the 22lr has very similar issues as these large calibers when it comes to tran-sonic instability.

[JEBar]

I have been working on a comfortable load my 45-70 to shoot 500yrd silhouettes for some months now. I haven't been able to do it with flat nose bullets. At 500 yrds they'll be all around the target high, low, right, left, or just fall out of the sky around 300yrds.

I've had both this issue with trying to shoot a bolt action 30-30 out to 500 meters. The 30-30 is not a 500 meter rifle, not in my hands.

first, I have nowhere to even try a 500 yard shot so I have no practical experience at making such a shot .... all I can go on is what are supposed to be reliable tables and other such data .... for our 45-70 with the 300 gr Nosler Ballistic Silvertips (Ballistic Coefficient 0.191) loaded to a muzzle velocity of 2228 fps, if we sight it in 8" high a 25 yards, it should be dead on at 500 yards .... I'd sure love to give that a try ..

I do have 100 yard experience firing Nosler's 150 gr Ballistic Silvertips (Ballistic Coefficient 0.232) at 2180 fps out of our vintage Model 94 .... it is the most aerodynamic 30-30 bullet I've ever fired .... using the same tables, if sighted in 7" high at 25 yds, it should be zeroed at 500 yards .... here again, its sure a shot I'd love to try

[Ojaileveraction]

first, I have nowhere to even try a 500 yard shot so I have no practical experience at making such a shot .... all I can go on is what are supposed to be reliable tables and other such data .... for our 45-70 with the 300 gr Nosler Ballistic Silvertips (Ballistic Coefficient 0.191) loaded to a muzzle velocity of 2228 fps, if we sight it in 8" high a 25 yards, it should be dead on at 500 yards .... I'd sure love to give that a try ..

That my friends is a serious NEED FOR SPEED.
And using my tables I can see that the 300gr bullet will drop below the speed of sound somewhere around 300 yards.
Maximum comfortable for me is a 300 gr bullet w about 1450fps muzzle velocity.

[JEBar]

That my friends is a serious NEED FOR SPEED.
And using my tables I can see that the 300gr bullet will drop below the speed of sound somewhere around 300 yards.
Maximum comfortable for me is a 300 gr bullet w about 1450fps muzzle velocity.

with a muzzle velocity of 1450 fps, a 300 gr bullet would have to follow one heck of an ark to get out 500 yards .... something like 17" high at 25 yards and 114" high at 250 yards .... given, a 45-70 isn't generally considered to be a long distance rifle ....for me to have any chance of coming close at that type of distance, I'd want as flat of a trajectory as is possible .... without the benefits gained from firing an aerodynamic bullet, I'd sure want all the speed I can get

[DAVIDF]

I have not noticed much difference in accuracy whether a load has a muzzle velocity a little over the speed of sound or under. It may effect it slightly with a 200gr RNFP plated bullet from X-Treme. I chronographed my most accurate load with that bullet at 1068 fps. However, when driven slightly faster at an average of 1139 fps it is perhaps only slightly less accurate and that may just be me. No fliers with that load to indicate something is wrong.

My most accurate load is a 240 gr RNFP HC coated bullet from Missouri sized at .432 over 7.1gr of Red Dot. Its average is 1154 fps. That load is accurate at 210 yards. However, it may be the bullet more than anything. I loaded it with only 5.0 gr of Red Dot with an average velocity of 861 fps out of my Big Boy. I was able to consistently hit a 12" X 20" steel plate at 210 yards once I figured out the proper hold. The height of the plate due to the extreme angle it is mounted is closer to 14". With the faster load and the rear sight elevator set at its highest setting, I hold on the bottom of the plate and the point of impact is about 2/3 up the plate. With the slow load and the sights set the same, I hold on the top and the point of impact is slightly low of the middle of the plate. Using a ballistics calculator, looks like the slow load would be hitting somewhere around 25" high at 100 yards.

I have yet to connect with that steel plate at 210 yards with other bullets loaded to 1220 fps and slower. Maybe they become unstable at those distances? But, all of those loads would have passed thru the sound barrier before 50 yards and they are quite accurate at 100 just not at 210 yards apparently.