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Bigslug
Posts: 9,860 Senior Member
I figured some would find this interesting. . .
Got the new baby down to the lab on Dad's back porch to begin preliminary load work the other day and put it on the "Lead Scale" prior to getting started. Just under nine pounds dry; just over with a walking load of seven rounds.
What's become our practice with any new rifle is to get as exact measurements of the bore an chamber as we can to help with cast bullet selection - often using the data to design a custom mold. A few steps to this:
1. We have a set of machinist's pin gauges which we use to determine the bore diameter. .299" in this case.
2. We then drive a pure lead slug down the bore to get an impression at groove diameter. This has 5R rifling, so we need to use a V-anvil micrometer to get a read on the offset impressions. .308" (Shocking!
)
3. Then we take a fired case and pour it almost full of molten lead - about halfway up the neck. After cooling, we chamber this with either a pure lead bullet cast for the purpose on top, or, if that won't chamber, we run it down from the muzzle. We then take a close-to-bore-diameter steel rod that we strategically mask with painter's tape to protect the barrel and hammer the slug down into the lead-filled case. The result is a perfect impression of the chamber, leade, and throat, ideally, just past any taper from the chamber reamer:
When ordering cast bullet molds, this allows you to look at the blueprint for the mold in question - or design your own - to choose something that will chamber smoothly and transition well into the lands. My phone rang in the middle of this and "stuff" intervened, so measuring was a bit of a rush job, but kinda like so:
You can get an idea of the taper of your throat and choose or design bullets accordingly.
As you might recall from the acquisition thread on this rifle, initial findings indicated that the throat MIGHT be too long to get good results with the 150 grain Barnes TTSX I had in mind (or the bullet's full diameter shank is too short), so along the that line of thinking, I ordered up some likely all-copper hunting options:
The initial test fit of the 150 grain TTSX on the left indicates that it is, or is almost completely out of the case by the time the ogive hits rifling. The 165 grain TTSX and 165 grain TSX to it's right are designed to have a less pointy nose and a longer bearing surface. The goal here is to come up with a cartridge that fits this magazine (short-ish), and presents the bullet with a shorter jump to the lands.
And that's where I ran out of time. Next step will be to get all three into the Stoney Point COAL tool and see what these give us.
As an aside, I did get ten of the cast bullet, 2100fps loads cooked up for another rifle (pictured at the right of my "blueprint") downrange at 100 yards:
Good enough for offhand practice slaughtering milk jugs.
To Be Continued!
Ruger Hawkeye '06: The Weird Science Begins
Bigslug
Posts: 9,860 Senior Member
I figured some would find this interesting. . .
Got the new baby down to the lab on Dad's back porch to begin preliminary load work the other day and put it on the "Lead Scale" prior to getting started. Just under nine pounds dry; just over with a walking load of seven rounds.
What's become our practice with any new rifle is to get as exact measurements of the bore an chamber as we can to help with cast bullet selection - often using the data to design a custom mold. A few steps to this:
1. We have a set of machinist's pin gauges which we use to determine the bore diameter. .299" in this case.
2. We then drive a pure lead slug down the bore to get an impression at groove diameter. This has 5R rifling, so we need to use a V-anvil micrometer to get a read on the offset impressions. .308" (Shocking!
)3. Then we take a fired case and pour it almost full of molten lead - about halfway up the neck. After cooling, we chamber this with either a pure lead bullet cast for the purpose on top, or, if that won't chamber, we run it down from the muzzle. We then take a close-to-bore-diameter steel rod that we strategically mask with painter's tape to protect the barrel and hammer the slug down into the lead-filled case. The result is a perfect impression of the chamber, leade, and throat, ideally, just past any taper from the chamber reamer:
When ordering cast bullet molds, this allows you to look at the blueprint for the mold in question - or design your own - to choose something that will chamber smoothly and transition well into the lands. My phone rang in the middle of this and "stuff" intervened, so measuring was a bit of a rush job, but kinda like so:
You can get an idea of the taper of your throat and choose or design bullets accordingly.
As you might recall from the acquisition thread on this rifle, initial findings indicated that the throat MIGHT be too long to get good results with the 150 grain Barnes TTSX I had in mind (or the bullet's full diameter shank is too short), so along the that line of thinking, I ordered up some likely all-copper hunting options:
The initial test fit of the 150 grain TTSX on the left indicates that it is, or is almost completely out of the case by the time the ogive hits rifling. The 165 grain TTSX and 165 grain TSX to it's right are designed to have a less pointy nose and a longer bearing surface. The goal here is to come up with a cartridge that fits this magazine (short-ish), and presents the bullet with a shorter jump to the lands.
And that's where I ran out of time. Next step will be to get all three into the Stoney Point COAL tool and see what these give us.
As an aside, I did get ten of the cast bullet, 2100fps loads cooked up for another rifle (pictured at the right of my "blueprint") downrange at 100 yards:
Good enough for offhand practice slaughtering milk jugs.
To Be Continued!
WWJMBD?
"Nothing is safe from stupid." - Zee
"Nothing is safe from stupid." - Zee
Replies
Whatever keeps you out of the brothels.
dressed and ready to go is about what I look for as a comprise between shootability and being easy to carry. I *think* my 7mm Rem Mag is around that, and my 7mm08 weighs in at 8.5#.
"Slow is smooth, smooth is fast, and speed is the economy of motion" - Scott Jedlinski
One gets hooked on sub-MOA deer rifles - I feel obligated to keep the streak alive!
"Nothing is safe from stupid." - Zee
There's the old school method of painstakingly scraping wood to achieve 100% bedding contact. Then there's the British SMLE steampunk method of supporting a barrel with rings and screws and springs and saddles. Then there's the Remington 700 sporter method of strategic contacts on the barrel.
Then there's this injection-molded thing:
I will give Ruger this: the action bedding surfaces are great. It fits snug and I don't think there's anything that needs to be done there. As to the barrel channel. . .they were clearly trying for something like Remington's front-of-stock contact point providing upward pressure, but the sides of the channel closed in and were making random hairline contacts or gaps along the length of the barrel. Nuts to that! It's now a 2-dollar bill thickness free float back to the Knox form, and we'll see how that does next time out. If that's a dud, I'll Acraglas back in at just the forend tip and leave the rest contact-free.
In handload prep, I received my test bullet samples and got them on the Stoney Point tool.
Not the best photo, but this is the Barnes 150 grain TTSX pushed out of the case to the point it makes contact with the lands. (The magazine length requires it to be seated with the boatail somewhat back past the rear of the neck.) This bullet is making about a 1/16th" to 1/8th" jump between the case neck releasing the shank and the ogive hitting rifling.
This may or may not be detrimental to accuracy - on the one hand, the bullet has that wobble room to get cockeyed, but on the other, this may help it self-center in the bore. The 165 grain version of this bullet with a fatter ogive profile still has about 1/8th" of shank still inside the case at the point of handoff to the rifling.
In the event I get very bored, I have the 168 grain version, which has an identical nose profile to the 150, but a longer shank that maintains case grip up to the point of rifling engagement. The magazine dictates it'll be seated to the same OAL, so this makes it a natural to wring out this case-grip theory. It's probably not a bullet I'd want for this rifle to hunt with, but in the interest of serving the Science (!) and Learning Stuff, it may get a trial if Nirvana is not reached with the lighter weights. If I get very, VERY bored, I could test the opposite extreme with the 130 grain version - also the same nose and seating depth, but an even bigger jump across open space.
But aside from this compulsive dive down an internal ballistics rabbit hole, I REALLY like this rifle. Between the big bolt knob, controlled feed combined with the light weight, it's super smooth and a joy to run. I've never taken my Gunsite Scout out of the stock, and so have never had a proper look under the hood of this M77 system. Their 3-position safety is a thing of simple beauty, and the front action screw and bedding surface pulling back and down at a 45-degree angle just makes good sense. If you have an appreciation for how a good machine operates, there is a lot to like here.
"Nothing is safe from stupid." - Zee
Truly, this one may be a poster-child for the saying that ignorance can be bliss. Pop and I have both accumulated a number of antiques over the last 15 years which have REQUIRED us to think inside this particular bullet-fitting box to get them to shoot reliably and well. Prior to that, it was Highpower competition with custom-cut chambers with MUCH tighter runs into the throat. Therefore, the stuff that I THINK I know is causing a harder look at this rifle than is possibly required. It's a neat brain puzzle, and I'll know more when it's done. So much for easy.
As a random aside, we may have a glimpse into what started the belief/argument that the .308 Winchester is an inherently more accurate cartridge than the .30-06. The .308 doesn't have the historical baggage of occasionally needing to be compatible with 220 grain round noses and nobody ever wanted one to be factory-throated to accommodate them. I've bitched about the close confines of the .308's often short magazine length, but I suppose the smaller box to work in keeps everybody's throats and bullets in a tighter range of extremes.
"Nothing is safe from stupid." - Zee
"Slow is smooth, smooth is fast, and speed is the economy of motion" - Scott Jedlinski
The first wave of pistol red dots showed up just as my eyes started to die, so here I am - a technology-resistant Luddite being kept "alive" by 21st Century life-support that eliminates the need for the "bifocal tilt" to see a front sight clearly. You can rest assured I'm aware of the irony...
As to the rifle deep-dive, this one presented quirks for which the process of measuring a gun for cast bullet selection may provide some solid answers for jacketed / monometal copper. It seemed a worthwhile way to expose y'all to some of the tools in that kit, and truthfully, I'm a little surprised I'm applying them for this purpose.
What all of this super geeky, nerdy detail does is give a lot of insight into what a particular barrel might need. The Old Man (all HIS fault, BTW) and I have used this to design lead bullet molds that place the base right at the back of the neck while contouring the nose for best interface with the lands - and do this all for a 100+ year old antique for which Sierra Matchkings don't even exist. With this .30-06, it did a pretty good job of telling me which bullets I should probably not rush out to buy several hundred of.
With the relieving of the barrel channel, I'm going to re-shoot the same factory ammo I did my initial groups with to see what the net improvement is. Good thing this is all starting right at the END of deer season - should be ready to rock by next October!
"Nothing is safe from stupid." - Zee
"Slow is smooth, smooth is fast, and speed is the economy of motion" - Scott Jedlinski
Other bullets, rifles, and or cartridges the information might prove useful.
The Item of Worry here is not so much setting the bullet close to the lands with the round pre-ignition. My Ruger Scout proved that wasn't patently necessary with the 130 grain TTSX which was forced back into the case farther than desired by the short magazine length.
With the mag length for this rifle, any of the Barnes bullets are going to be travelling a good distance before contacting the lands. The difference between the 150 and 165 grain versions is that the heavier bullets will still have a little grip inside the case when that occurs, while the 150 grainer will be floating in space, un-guided by anything for about an 1/8th inch.
With fire-formed brass neck-sized only, the notion is that the bullet will be concentrically centered in the chamber. The 165's will have a nice handoff from case to rifling; the 150's will either naturally funnel in happy and use the ogive to self-center, or they'll rattle across the gap and scatter to the winds. The HOPE is that the 150's will shoot well at a fairly screaming top speed. The EXPECTATION is that the 165's will shoot better. The gun will get that which groups best.
Since I had a good bit of the 150 grain Remington factory load, I'm probably going to empty out the rest of it and use those cases to generate the hunting loads (unless the brass just turns out to be totally inconsistent crap). I'll probably do that on Black Friday to avoid "civilized" places. Will probably be hitting the load development hard between Xmas & NYD, since my aerospace engineer cousin will be in town and he appreciates this kind of madness.
"Nothing is safe from stupid." - Zee
I did a re-shoot of the factory ammo to see what's happened as a result of the free-floating. Pretty uninspiriong - 10 shot groups spraying into just under 4 MOA, with the bulk of them running around 2.5 MOA
I also shot some 180 grain Winchesters that I had not previously fired:
So ten shots into four inches. . .but five of those ten into just over half an inch.
Considering that I was shooting a peep-sighted Martini Cadet into tighter than this on this same morning, I can safely say it ain't me. File it under (a.) not entirely trusting factory stuff, or (b.) things that make ya go "hmmmm". At any rate, the 150 grain Remington continued to be the worst, lending some creedence to the theory that this rifle wants a longer bearing surface / less bullet jump.
Got the ladder test loads ready to go:
Slight omission in the notes: COAL of 3.24" fits the mag; 3.365" kisses the lands, so 1/8" off the rifling for the 165 TTSX. The 165 TSX is pretty similar.
Initial fuel of choice will be H4350. See ya in 2 weeks!
"Nothing is safe from stupid." - Zee
I’m what order? Are those the first five and then group opens up or just randomly threw a round into an existing cluster? If I missed this I’m sorry, did you bed the action?
It’s a °IIIII° thing 😎
No bedding of the action as of yet, but the knox at the back of the barrel could be clearanced a little more thoroughly, and a dose of Dev-Con is certainly something I can do and am not shy about. The action fit seemed pretty solid, but now that I think about it, a slight pinch on a molded stock like this would be all that's needed to give that impression.
I'm digging everything else about the rifle - a lot - so a bit of extra coaxing doesn't bother me. To quote a Disney villain, "That's what I DO. That's what I LIIIIIIVE for!"
"Nothing is safe from stupid." - Zee
These groups are 15 shots, each increasing by 0.2 grains of powder over the last - so a three grain spread from start to finish.
First off, the 150 grain Tipped TSX:
The photo doesn't quite tell the story properly. The first 5-6 all hung tight to the middle, then they started creeping upward as the charges increased. The first 4 in the string were a little erratic in velocity, but the next five were all very close to about 3025 fps. Gonna run another 10-15 with a single charge in the middle of that flat spot and see what it delivers.
Here's where we start to get giddy. This is the 165 grain TTSX:
This is possibly one of the tightest workup groups Pop and I have run in farting around with this process for a LONG time - 15 rounds over three grains of powder, and the point of impact did not appreciably move at all. A string of five of these clustered nicely around 2800 fps. We're going to hopefully pin the magic in the middle of that.
And then we have Extra Giddy with the 165 grain non-tipped TSX:
Velocities ran pretty close for both 165 grainers, so they'll probably get the same 2800 fps charge test. They don't hit book max for another full grain, so I may burn the rest of the boxes on seeing where General Yeager's demon lives. The 150's got to a compressed charge, before I got to the top, but 3000 fps was the target anyway.
So #1: I'm very pleased with the day's events.
And #2: I've learned that the preceding factory ammo SSSSUUUUUUUUUCKS!
Might get out to test the refinements between Christmas and New Year. Got visiting relatives, so it'll depend on whether my cousin has time for Weird Science.
To be continued!
"Nothing is safe from stupid." - Zee
It’s a °IIIII° thing 😎
Rate of fire is pretty quick - pop the shot, write down the shot location and speed on the data card, punch out the next. Yes, they're usually pretty warm at the end of 15-20 shots (which is the limit of what our old chronograph's brain will hold). At that point, we work on something else while the barrel returns to room temperature. If a barrel acts like it's going to be a chronic heat wobbler (blessedly few of those), I'd consider inserting more pauses.
Fouling. . .I'm pretty meticulous with my chipmunks during barrel break in, and it seems to work for giving me a smooth tube that does not egregiously collect copper, and these Barnes slugs don't really seem to lay down much, if any. Over the course of a project like this, I don't worry about it. I blow up a milk jug with a fouling shot to get any CLP out of the bore and then move to paper and the chrono. For hunting season, I thoroughly clean out the residue from my cast bullet practice loads, dry it out with alcohol, fire 3-5 shots to confirm zero, and leave it alone until something dies or the season ends, whichever comes first.
"Nothing is safe from stupid." - Zee
It’s a °IIIII° thing 😎
After the initial velocity workups, the 150 grain TTSX showed two flat spots on the curve where the velocity didn't really change over 6-8 tenths of a grain. Both of the 165's had one - in about exactly the same charge range. Loaded up ten rounds in each of those flat spots and got out with them yesterday.
So for the 150 grain TTSX. . . The lighter charge of 60.3 grains of H4350:
And the hotter one at 61.4:
Pretty much identical numbers for consistency on the chrono, but the light charge for sure ain't getting it done for accuracy. I think there might be hope for the hotter charge considering that it's ten shots with no cooling off and pilot error on the shot release is always a consideration.
The last group of the day was with the 165 TSX (non-tipped at 55.4 grains of H4350):
The light was starting to get weird toward the end of the day, so that might have been a factor, but the earlier horizontal stringing seemed to return for this one. Weird.
But what looks like the winner at this point is the 165 grain TTSX with the same powder charge:
The high left shot was a called bad release, so we're hovering right around 1 MOA with 2800 fps - maybe a touch slower on a cold day. I'd hoped for more speed with the lighter bullet, but I think this will be where we live.
I may load up the last few remaining 150's at the hotter charge to see how they do on a second attempt, but the vibe I'm getting is that I was probably correct on the "too much bullet jump" theory, so this thread may not be QUITE done, but for the moment, I hope you enjoyed the trip.
"Nothing is safe from stupid." - Zee
It’s a °IIIII° thing 😎
I went ahead and ordered more of the 165gr. TTSX's Since I've got a good bit of that Remington factory ammo that doesn't group, I've opted to use that brass for the hunting loads. Turns out there was some matching stuff in the "archival" .30-06 brass stash so all that was needed to get that ready was to fire form it with a scratch load.
You may remember the thread I posted some months back about my Old Man's .30-40 1895 Winchester. He had some bullets left over from his custom mold for that, and voila! scratch fire forming loads:
Shot three ten shot groups with it after confirming the 150gr TTSX load was a dud in this rifle. They started good and got better as the bore conditioned into the lube. And the final result was pretty much "HOLY CRAP!"
The intriguing bit here is that we have three versions of this bullet mold differing mainly in length for the necks of the .30-30, .30-40, and the .30-06 - - but the Krag version was what was on hand. It's technically too long to load in the '06, with it's gas check shoved back past the back of the neck, but ya can't really argue the proof.
This is a first - we're sitting here asking ourselves how to get it to shoot as well with jacketed/copper as it does with cast. Screw it - I'm taking the win.
"Nothing is safe from stupid." - Zee
That load certainly made us go "hmmmm". I fired the last half dozen or so at an unused target left at 200 - didn't recover it, but the grouping seemed to hold.
The bigger irritation of CA is not that I'm hunting with dollar-a-shot copper bullets. They kill VERY effectively and once the science is done and you have a load, you don't go popping them off like discount .22's. What makes me cranky is the meat science I can't do with lead. But I CAN at least practice like crazy with 'em.
"Nothing is safe from stupid." - Zee