250gr A Tip in a 308

[rardoin]

To paraphrase Robert Ruark, Doug...."he was looking at you like you owed him money".

 

[davidjoe]

To paraphrase Robert Ruark, Doug...."he was looking at you like you owed him money".

Doug is in charge of collecting “new member” dues now and keeps trying to shake him down, murmuring you see, this is why you’re the only one.

 

[dskogman]

It's very distracting when you hear this huge splash somewhere behind you when you are trying to shoot. Some people (Tim) have been known to leave the range.

With a OAL of 3.5 QL shows 74K psi with 49 gn of H4350 and a 110% fill.
The max is around 46 gn, 60K psi, 103% fill and 2400 fps

 

[davidjoe]

It's very distracting when you hear this huge splash somewhere behind you when you are trying to shoot. Some people (Tim) have been known to leave the range.

With a OAL of 3.5 QL shows 74K psi with 49 gn of H4350 and a 110% fill.
The max is around 46 gn, 60K psi, 103% fill and 2400 fps

We have to make sure that alligator is present and healthy for Tim’s whole life.

That load of 50.0 of reloader 17? ... was it, hopefully, very much above this level?

** closer to 3.4 AOL than 3.5.

 

[Ned Ludd]

... It’s a fine line between those two, but Hornady made this Red Pill, and there’s no choice but to see how deep the rabbit hole goes.

The good news is that the rabbit hole is far too small for a human body to fit down in it. The bad news is two-fold: the rabbit hole is more than large enough to accommodate all your money; and because it is not large enough for a human body, the process can be repeated many times.

Just out of curiosity, if you're really that interested in pushing these 250 A-tips out of a .308 case, I have to assume the uber-high BC is at least part of the motivation. Along that line of thinking, have you ever given any thought to trying the Warner Flatline 198s? They have almost as high a BC as the 250 A-tips. Of course there are other considerations to running them, including cost, the need for a relatively short freebore (0.100" to 0.120"-ish), and an 8-twist barrel. Some have tried them and experienced unexplained vertical, which is one of the reasons why you don't see them on the line at very many F-TR matches. Nonetheless, driving the 198s to respectable velocity out of a .308 Win case is likely a much easier task than the 250s. Having flirted with the rabbit hole on numerous occasions myself, the primary conclusion I have come to is that the end benefit for me has usually been a much lighter wallet, but little else.

 

[davidjoe]

^ I haven’t tried them, yet. ^ I can sure catch myself gazing into the halo cast by the latest, greatest, bright and shiny objects. “Where is the checkout button.” It’s true, though, that besides Uber BC, there are some other (subtle) motivating draws tugging attention toward the red brand. Yes, a little bit of sentimentality for mine and everyone’s first good loaded ammo when we got some $.

Hornady, is trying very hard here, like a restaurant receiving a culinary critic, and it’s difficult to describe all the intangible ways. From the meticulous twin trays packaging with logo felt polishing bags, to bullets that look like they were made slowly, as if each one of them was going to be enlarged for a glossy brochure or press picture. That “tip” is only about 1/4 of the aluminum used. The copper jackets show no sign of stress or brittleness and remind me of expensive oxygen free copper we shelled out for in the 90’s on audio cables.

And they are clones of each other. Pilots and engineers used to informally summarize a plane’s aerodynamics or flight characteristics in terms saying a feature of the airframe “just looks right”, as a necessary starting point.

The whole line, much wider than the few have, is an offshoot of the 50 BMG.

 

[Evan]

Yes, a little bit of sentimentality for mine and everyone’s first good loaded ammo when we got some $.

Hornady, is trying very hard here, like a restaurant receiving a culinary critic, and it’s difficult to describe all the intangible ways.

I too have a sentimental spot for Hornady. They have always felt like a company that is trying to meet our demands and make better stuff, unlike many of the other companies in the gun industry that seem to do a great job of failing or lowering their quality all the time *cough* Remington *cough*

 

[Sandstorm]

Right you are David...they sho do look mighty good too...

And they are clones of each other

 

[Ned Ludd]

^ I haven’t tried them, yet. ^ I can sure catch myself gazing into the halo cast by the latest, greatest, bright and shiny objects. “Where is the checkout button.” It’s true, though, that besides Uber BC, there are some other (subtle) motivating draws tugging attention toward the red brand. Yes, a little bit of sentimentality for mine and everyone’s first good loaded ammo when we got some $.

Hornady, is trying very hard here, like a restaurant receiving a culinary critic, and it’s difficult to describe all the intangible ways. From the meticulous twin trays packaging with logo felt polishing bags, to bullets that look like they were made slowly, as if each one of them was going to be enlarged for a glossy brochure or press picture. That “tip” is only about 1/4 of the aluminum used. The copper jackets show no sign of stress or brittleness and remind me of expensive oxygen free copper we shelled out for in the 90’s on audio cables.

And they are clones of each other. Pilots and engineers used to informally summarize a plane’s aerodynamics or flight characteristics in terms saying a feature of the airframe “just looks right”, as a necessary starting point.

The whole line, much wider than the few have, is an offshoot of the 50 BMG.

I totally get that. The only real reason one needs to justify a venture down the rabbit hole is that they can, right?


Besides which, as you've already clearly decided to take that little jaunt, I feel it is my obligation to assist you by bringing to your attention monolithic bullets that cost in excess of $1.50 each. You know, because you really want to get that "full rabbit hole experience". .

Nonetheless, no one would be happier for you than I if you can get the 250s working. I think you're asking an awful lot of a .308 Win F-TR setup with a bullet that heavy, but you'll certainly deserve a lot of credit if you can get them working. Best of luck!

 

[Kratos]

That load of 50.0 of reloader 17? ... was it, hopefully, very much above this level?

** closer to 3.4 AOL than 3.5.

I am fascinated by this experiment and ran these numbers in Gordon’s Reloading Tool.

50 grains RL17, OAL 3.4: 89,600 psi. MV 2685 fps. 105% fill.
47 grains: 70,200 psi. 2543 fps. 99% fill.

 

[davidjoe]

Kratos, that pressure info on the 17 is actually very reassuring to know. I should probably get one of the apps myself. The new gun should be picked up and on the range by 2:00 today, and I know it could be apples to oranges, but I could get good reloads with 47.0 of 4350, based on the feel of 3-4 with a few I kept using, probably 7-8. I wanted to use 48++ but the compression ringed the bullets. Especially on load number one. This chamber is .10” longer for that reason.

The bullets don’t always seat straight using only portions of the neck and compressing them, even seating them with several little turns in the shell holder, but one of the earliest things I had tested for on paper is whether the groups would reflect the culled, most-misaligned rounds, or not. Seemingly this long body in the bore has no ability to resist truing up when chambered, which is good.

 

[Kratos]

Kratos, that pressure info on the 17 is actually very reassuring to know. I should probably get one of the apps myself. The new gun should be picked up and on the range by 2:00 today, and I know it could be apples to oranges, but I could get good reloads with 47.0 of 4350, based on the feel of 3-4 with a few I kept using, probably 7-8. I wanted to use 48++ but the compression ringed the bullets. Especially on load number one. This chamber is .10” longer for that reason.

The bullets don’t always seat straight using half of the neck and compressing them, even seating them with several little turns in the shell holder, but one of the earliest things I had tested for on paper is whether the groups would reflect the culled, most-misaligned rounds, or not. Seemingly this long body in the bore has no ability to resist truing up when chambered, which is good.

Obviously this is a simulation and may not be perfectly accurate. It helps to true it to MV and use the actual case volume for your brass, but I've found it usually in the ballpark for most parameters. I highly recommend GRT, it is much more user friendly than QL, has more functionality and is actively updated. If you do the Patreon you also get excellent support from the author and more frequent updates.

 

[davidjoe]

I really like the information and layout they utilize. I sure can’t miss the warning notice. There is probably some very limited wiggle room in play with choices regarding the throat in each barrel, rifling, diameter, etc., but generally not a lot.

It also makes me wonder how close the standard FTR load of say 2,680-2,700 with a 200, (44.5+ Varget) would be to the line. There is definitely a hard and fast ceiling on how fast these can go, presently. The bulletin has featured newly-developing steel head rifle “brass” specifically to shoot at these pressures where the primer falls out of actual brass, presumably disposable, but I think several product paths already exist.

Based on your data, the case, on volume itself, can indeed hold powder sufficient to push these bullets to the velocities 200’s go now, which if tunable would make them basically uncatchable in wind at least in TR, because unlike trying to do the same thing with 7’s or even 30’s in Open, they aren’t going to get so hot as to blow up at that speed.

When I saw those steel experiments described, it did make me wonder - what would TR as a division say to something like that? They are “rated” for such extremely high pressure, in the conventional terms we are used to. And there is already the discardable steel case loaded ammo occupying the lower cost end of the market, (which may or may not be any stronger than brass if formed thinly), that means in theory there are new, empty shells.

 

[Turbulent Turtle]

To put everyone's mind at ease, I am squadding David on target 47 this Saturday, relays 1, 2 and 3.

I want the alligator between me and David; it's safer.

 

[davidjoe]

If for some reason I don’t arrive Saturday, and didn’t cancel in advance, it means, yup, the load wasn’t safe. .

 

[Kratos]

It also makes me wonder how close the standard FTR load of say 2,680-2,700 with a 200, (44.5+ Varget) would be to the line.

So it looks like maybe the calibration is a bit off given the numbers you provide, because this is the default sim:


When I recalibrate using 2700 @ 44.5, we get this:

 

[davidjoe]

That’s probably right for TR loads, after all federal gold medal match factory ammo attains only that same velocity with a much lighter 168 grain bullet.

 

[Ned Ludd]

Davidjoe - FWIW, for a typical 2650 fps F-TR load velocity from a 30" barrel, QuickLoad predicts pressures in the 61-62K psi range for the 200.20X bullet over Varget in Palma brass with the bullet seated at a COAL of 3.100" to 3.120", which I think is a little more realistic than a COAL of 2.900". Standard .308 Win brass will only survive that level of pressure for maybe 4-5 firings. However, .308 Win Palma brass should be good with such loads for at least 8-10 firings, or even more. Palma brass seems to withstand even loads predicted to be in the ~65K psi range, such as hitting the higher node (2700+ fps) with the 200.20X over Varget in a 30" barreled rifle. I once accidentally loaded and fired some rounds in Palma brass with a 210 gr BTHP .30 cal bullet that were subsequently predicted by QL to be in the ~68K psi range. Although that is a mistake I try very hard not to ever repeat, the brass suffered no obvious ill effects from a single firing at that pressure (i.e. the primers were not cratered or excessively flattened, the primer pockets remained tight, the casehead did not exhibit excessive expansion, etc.). Nonetheless, just be cautious and safe when working up your test loads with the 250s. Assuming you successfully survive the load development process, you'll also want to keep your eyes peeled for the alligator at the match. He may not take kindly to the muzzle blast your load might generate.

 

[davidjoe]

I have a couple of issues with the present action that I volunteered for the potential harder bolt closes and opens of this project. I had selected a single shot stainless 700, plain Jane non-40-X and not trued.

I have some rounds down the barrel, now. It has a scope base alignment issue that bothers me, which I must have forgotten about, and also I do not think it will shoot groups as small as alternatives that I have on hand. So the barrel is coming off and I’ll put it on probably a 40-X.

That’s a single gun issue as opposed to general load question, and as to the second, I did fire rounds with both 48 and 49 grains of 4350. There is no hard bolt lift whatsoever with either charge. You’d never know it hadn’t been a factory round. To me, recoil was not bad as I could easily watch the round impact by the rise of splash at 600 yards behind the frame. It takes a long time to arrive.

CCI 41’s and Palma brass can handle a lot of pressure, and the barrel being new provided a little more resistance. There is no gas leakage or edge squaring of the primers, but they do crater. Interestingly there isn’t any real appearance difference between 48 and 49 grains. Because that bolt has a plunger, there is the faintest of a circle’s shadow that enlargement reveals, but it is not close to high enough for any brass shearing or smearing and is actually pretty hard to see unaided.

Less powder to tune an accurate load with and more easily seat bullets is the near term goal, but is nice to know that nothing dramatic is going to occur with 4350 and 41’s. I would not use any other primer though.

 

[davidjoe]

This is a close up of the cratering with 49.0 grains of 4350 with the 250 A-tip. Too much powder and actually difficult to bullet seat. Over pressure, but probably not quite meeting the expectations of pressure signs for that load, at least mine. Some of my rifles show similar cratering with factory rounds.

The plunger circle is apparent. It’s something of a biased indicator because a lot of bolts don’t have a plunger hole, but would leave that mark if they did, with the loads run.