I'm now a believer in heavy crimping

[pitted bore]

Funny you mentioned that about the 45/70. Just saw this in the latest American Rifleman:
<image shows 45-70 data with 300s @ 1908 & 1831>
...and that's with an 18.5" bbl. We're beating that using a 50gr heavier bullet and 2.5" less bbl. ...

TT-
I think the reason for this is that the 45-70 ammo is limited to the SAAMI spec pressure of 28,000 psi. For interior ballistics, the rule is still TANSTAAFL.
--Bob

[wildcatter]

Funny you mentioned that about the 45/70. Just saw this in the latest American Rifleman:
<image shows 45-70 data with 300s @ 1908 & 1831>
...and that's with an 18.5" bbl. We're beating that using a 50gr heavier bullet and 2.5" less bbl. ...

TT-
I think the reason for this is that the 45-70 ammo is limited to the SAAMI spec pressure of 28,000 psi. For interior ballistics, the rule is still TANSTAAFL.
--Bob

Ah-Ha! But then again, even these paltry Saami Spec 45-70's, did Yeoman's work during the bygone Buffalo days.

To be honest, there are three 45-70 load groups, one is that paltry Saami spec and has to be, because we are still shooting the falling-block weapons and they wont take the pressures of the other two. Second is for the 1886 Winchester Lever Action and that area of construction, the pressures are higher than Saami Spec. And Thirdly, there are loads made for modern rifles, at their much more capable pressures. We, can and do, outperform all of those loading, with the 450b.

The Saami Conundrum, brings up a problem we also have.

Just as in the 45-70, I say the Saami Spec for the 450b was too mild, at adoption. However, that's just me, and should you try to exceed Saami specs, well, let's just say a KABOOM may be in your life. For just as in the case of the 45-70, if you exceed Saami, you'd better know what your are doing and have your insurance paid up.

Other than killing yourself, one can see some impressive results, from "Safely" reloading the 450b..

..t

[TacoTaco]

Ok fellers, got another data set. Went out this afternoon with a repeat of the same loads as last time: 38/39/40/41 grains of 1680 under swaged 350gr Hornady Interlocks at 2.260 COAL. The only difference this time was a more moderate crimp vs the heavy crimp of before, and the use of virgin brass.. Here's the numbers:

38gr: 1760 Avg
39gr: 1802 Avg
40gr: 1819 Avg
41gr: 1829 Avg

So overall there was a 30-50fps loss using less of a severe crimp. I think I'm going to have to do a study of the life of the brass as a function of crimping to se if the velocity loss is acceptable. Still, these are damn good numbers.

Also, since in my last iteration I had pretty decent accuracy at 40 and 41gr, I split the difference and loaded up a string of 40.5gr. Interestingly, they averaged 1839 FPS, which is 10 higher than what 41gr got me. Accuracy was ok, but none of the strings were as good the original data set. Group size averaged 1.60 (40.5gr) up to 3.3" (38.0gr), with the overall group size around 2-2.5". The accuracy loss was a little unexpected and unfortunate, but I think I can work on that.

From a safety standpoint, I marked the bases with a sharpie. No unusual markings were found that suggested an issue with pressures. I measured for case expansion...the most I saw was .003-.004.

All in all Im still very, very happy with what Im able to do with these 350's. If I can match the accuracy of my original data again, I think this is a keeper of a project.

[Hoot]

My experience has been that minor variations we impart when crimping, when using a light to moderate crimp, has much more effect upon combustion, than the same degree of variation when using a heavy crimp. So much impact as to cause velocities to vary at or beyond the same effect as adding or removing a whole grain of a "slow for our caliber" powder like 1680. Less so for faster powders. So why not just cut to the chase scene and always use heavy crimps? Again from my experience, the heavier the crimp, the greater the impact upon accuracy. It's a maddening conundrum.

We are dealing with a table of many legs, one of which being too short, as we strive to home in on maximum velocity for what we individually believe is acceptable accuracy.





Hoot

[TacoTaco]

Nice analogy Hoot. The round giveth and the round taketh away.

So I went out to the range again today, this time with a set of 350's loaded at 40.5, 41, 42, and 42.5gr of A1680 @2.260 COAL. Heavy 45/70 mod crimp. Here's the results:

40.5gr Avg: 1859.8
41.0gr Avg: 1859.4
42.ogr Avg: 1872
42.5gr Avg: 1883.

The 42 and 42.5gr loads both had three shots in the 1950ish range, but then the last two just died off, dropping to the low 1800's. Not sure why, but it killed the overall average. Accuracy for all loads was pretty decent. (See below) All loads were using 8X Fired brass that was annealed @7X Fired, and rem 7 1/2 primers. No pressure signs noted.

With this last data set, I've decided to settle in on my load: 40.5gr A1690 @ 2.260 COAL. In all my testing it has been the most accurate, and averaged between 1850-1880fps. It seems to be the perfect combination of accuracy and power. As the more experience folks here have said, I could go higher, but in all honesty I really don't need to push it anymore than I all ready have. I'm scoring a 42 on the TKO table. That's insane. If I go any higher I'll have to explain to my wife why Im in Africa, because the only reason I would need that much power is because I'm hunting bull elephants. I think a 350 @ 1850 or so will do just fine on an Elk.

Here's the AAR with the 350's:


While I was out there I broke out some 250 FTX's I brought along. 38.0gr Lil Gun. 10 shots. One of the best groups I've ever put up. Have I mentioned that I love this round???

[Hoot]

That's a great 250 group!

IMHO, that weight resides at the 2/3 range of the sweet zone for our barrels using the right powders, in terms of ultimate accuracy. That range being 200-275gr. With the right bullet, you can probably move the upper end to 300gr, which puts the 250 smack dab in the middle of the sweet zone.

If the 450LM ends up kicking the heavyweights out the barrel to the same degree of faster over the 450b as it does the 230s, that sweet zone will increase. The price you pay for the "opposite yet equal reaction" is going to increase as well, so choosing the right caliber for your mission will become more important. IE Being a man of modest means, who yesterday moved his daughter into her college dorm room, I doubt I'll ever be able to bankroll a Safari out of state or country so my mission is more of a white tail and maybe, just maybe a black bear tag here in Minnesota, so I have no mission to justify the cost of adding the 450LM. I know from reading that some of you are more fortunate and I can't wait to see the hunting reports start rolling in from the commercial offering of that caliber, once it goes public.

Hoot

[TacoTaco]

Thanks for the compliments Hoot.

In my neck of the woods (Pac Nor West) Roosevelt Elk are the quarry Im after. Now, I could take one quite easily with a 250-275gr bullet. Not much in N America stands up to one of those hitting it a 2200fps. But, well...I like to tinker. Kind of like how hot-rodders are always looking for more horsepower. Do they really need it? No, but trying to get it is just as much fun as using it. I play with the heavies for similar reasons. Plus, if there was even a sliver of doubt that an Elk would stand up to a 250gr bullet, all of that is gone when a 350 is brought to the table!

I think next I'll be playing around with those 325 FTX's. After that I'm going to go back to the 230FMJ's and see if I can get those to finally work.

[Hoot]

WRT that "opposite yet equal reaction. In the annealing range report thread, despite all four loads using the same charge of Lil Gun. The 200 grainers, while traveling faster than the 250s. The recoil was like night and day. Neither was punishing, quite the contrary, but the 250s moved the gun around such that I had to reposition it in the bags every shot to score my hit. The recoil from the 200s surprisingly allowed me to keep the scope on the paper.though not surprisingly, not allowing the crosshairs to stay on the bull at 24x. So, some repositioning still had to be done before the next shot.

Now, I work with a fellow who uses a Remington 742 semi-auto .30-06 for local deer and despite the gun being heavy and the action taking some punch out of the shot, it definitely moves you around in the bags. The point being, though I'm starting to sound like a broken record. Our 450b can toss 200 grainers as fast, if not faster than a .30-06 can and the .30-06 is legendary for it's killing capacity using a smaller frontal area bullet than ours. While I'm loathe to refer to someone's spin on lethality. An online calculator I've referred to in the past gives the 200gr .452 bullet traveling at 2400fps an efficacy rating more than twice that of a 200gr .308 bullet, traveling at the same speed.

The broken record moral being if you feel comfortable hunting a creature with a .30-06 at modest distance, you can feel even more confident hunting it with the 450b using light, fast, flat, yatta yatta, 200gr bullets.

FWIW, though handicapped in some ways due to their shortness, the 450b throws 180 grainers as fast if not faster than a .30-06.

Hoot

[TacoTaco]

Hoot--How do the 200's hold up at those velocities? Most 200 and 225 bullets are designed around the 45LC/454 Casaul, right? Can they stay together at those velocities? Just curious....

This has always bothered me to no end. Why don't bullet manufacturers list the optimal muzzle velocities for each bullet they produce?

[Hoot]

Hoot--How do the 200's hold up at those velocities? Most 200 and 225 bullets are designed around the 45LC/454 Casaul, right? Can they stay together at those velocities? Just curious....

This has always bothered me to no end. Why don't bullet manufacturers list the optimal muzzle velocities for each bullet they produce?

Some manufacturers do.

By now, you probably have seen my FTX Comparison thread complete with water shots as well as the XPB water shots. In the case of all three in the FTX article, they were shot over 38gr of Lil Gun and like any cup and core, non-bonded bullet, they shed some, averaging around 70% retained weight. While we have no way of creating an analog between those multiple, tough milk jug walls and animal bone, my guess would be greater expansion after blowing through a full-on shoulder bone hit, again like any unbonded, unpartitioned, cup and core bullet. There's no way to predict how they will behave when you shoot real game until we start getting multiple post-mortem reports. A lot of big game have been effectively taken with regular, un-fancy, cup and core bullets. There comes a point where ya pays ya money, ya takes ya chances.

Now back to trying to get this ornery water softener to work right during the brine cycle.

Hoot