PSA 2nd Gen AR10 project ...

[Spindrift]

Nice shooting!

 

[popper]

What alloy are you using? I found ARcomp to give better results with less powder than varget in my long barrel (2750 avg) with 168 Amax (decent target bullet and cheaper). I've run up to 40.5 H4895, 2500 fps cast hard. Normally run H335 or 4895 @ 39gr for the 165 hard cast, heat treated. 4% Sb with some Cu. Never could get that carbine stock to shoot right off a bag, changed to a magpul straight bottom one. Interesting to see what fps you are at. Without the can I guess @ 2600.

 

[Ian]

Quickload says 2,390 fps at 43K psi peak, and just under 10K psi at the muzzle. Not too bad. I used 162 grain 312-155s and cases holding 54 grains if water, which are my own numbers. Bullet seated to crimp in the lube groove.

With the coating you lose some velocity due to low engraving pressure and bore friction, but the can gives some back. My loads predicted a little less than I actually measured with a Magnetospeed, so it's all a guess until actually measured.

I still get a chuckle out of the fact that many of us are pushing .30-caliber cast to the mid-2K range and nobody bats an eye. Far cry from the way the internet was just a few years ago.

 

[wquiles]

What alloy are you using? I found ARcomp to give better results with less powder than varget in my long barrel (2750 avg) with 168 Amax (decent target bullet and cheaper). I've run up to 40.5 H4895, 2500 fps cast hard. Normally run H335 or 4895 @ 39gr for the 165 hard cast, heat treated. 4% Sb with some Cu. Never could get that carbine stock to shoot right off a bag, changed to a magpul straight bottom one. Interesting to see what fps you are at. Without the can I guess @ 2600.

I have no freaking idea what my allow is. Over the years I have combined hard cast (20+) with pure lead, and some Tin, and after water quenching, it was usually in the 18-19 hardness (per lee hardness tester), but these have been PC coated and air-cooled, so not quite as hard as my normal alloy - these came at about 16 to 16.5 or so. These are slightly under the ideal .310", so I did coated them in Bens Liquid Lube on top of the PC just to try "seal" a little better, but I definitely need to cast again and size at .310" soon:

Ian, as to the actual load, so that your QL can be closer to mine, this is the label from this morning when I made these 40 rounds:

Now that I have polished the sharp edges, brass looks MUCH better (thanks again for the tip!), of course dirty since I shoot with the suppressor in place (except for lost cases - left to right, 10x each of 41-> 42.5gr Varget):

These were the cases with 42 and 42.5gr:

My QL estimates about 40Kpsi max chamber, and about 2300 fps out of my 18" barrel, for a nifty 1991 ft-lbs at the muzzle.

I know I need to check the "actual" speed of these, and I still have it on my list to by a LabRadar, but there is always a new project/stuff that I buy first, so I don't have it yet

Will

 

[Ian]

I used my actual weight of 162 grains, 42 grains, of Varget, and my case internal volume measurement for PMJ military brass that I've actually chronographed (suppressed) in my M1A with a different powder. Those things make a slight but imprtant difference to the accuracy if the prediction.

I'd skip the BLL next time and shoot them dry just to see if it improves. So far I have had no reason whatsoever to lube bullets in the LR-308. Also, if they're larger than .309" it's probably fine. Lots to play with, staying on the paper at these speeds isn't nothing so you're doing a lot of things already that the rifle likes, now it's just small tweaks.

 

[popper]

I BLLd over PC in 30/30, just keeps the bore shiny. I can drop a box loaded a while back to range with you name on it, harder alloy, prob. Next week.

 

[wquiles]

So far I have had no reason whatsoever to lube bullets in the LR-308. Also, if they're larger than .309" it's probably fine. Lots to play with, staying on the paper at these speeds isn't nothing so you're doing a lot of things already that the rifle likes, now it's just small tweaks.

Funny thing, is that this being a semi-auto, all rounds feed from the magazine, is still more accurate "for me" than the Savage 308 that I now want to sell. On the Savage I feed the rounds one at time from the "sled" magazine, tried various sizing options, 4x different bullet molds, and even at slower velocities than these, I never got the Savage to shoot cast as well as this seme-auto does.

EDIT: The other thing I really love about the semi-auto vs the bolt in 308, is the "felt" recoil. I love the "softer" felt recoil on the semi-auto, even when the semi-auto is about 1 pound lighter

I BLLd over PC in 30/30, just keeps the bore shiny.

Yes, I figured it couldn't hurt

I can drop a box loaded a while back to range with you name on it, harder alloy, prob. Next week.

I would love to try for sure, to see if harder alloy will help the groups - thanks!

Will

 

[Ian]

Jury is still out on the overcoat, cold-bore flyers and so forth, and not much in the way of tight, 100-yard, high-velocity, 10-shot groups been posted using it. 3 MOA isn't bad, but I would like to see side by side comparisons with a light cleaning in between before making any conclusions about the BLL over PC effect.

I might give it a go but not in my LR-308 because I stumbled upon a system of perfection for the rifle's purpose which allows me to clean the barrel and put the next shot dead center of the group, or shoot it dirty and first shot be on the edge of a an easy 1.5 moa group.

Do you have any Reloder 7 Will? If so I can send you some of my MP 30 Silhouette bullets to try.

 

[wquiles]

Jury is still out on the overcoat, cold-bore flyers and so forth, and not much in the way of tight, 100-yard, high-velocity, 10-shot groups been posted using it. 3 MOA isn't bad, but I would like to see side by side comparisons with a light cleaning in between before making any conclusions about the BLL over PC effect.

I might give it a go but not in my LR-308 because I stumbled upon a system of perfection for the rifle's purpose which allows me to clean the barrel and put the next shot dead center of the group, or shoot it dirty and first shot be on the edge of a an easy 1.5 moa group.

Gotcha - a good experiment to try out with and without BLL once I get something a little more solid/consistent.

Do you have any Reloder 7 Will? If so I can send you some of my MP 30 Silhouette bullets to try.

I don't have any R7, so yes, please. That would be great to try both the powder and a few of your bullets!

 

[Ian]

I can't send you the powder but can send some bullets. Send me a PM with your address and I'll ship out some to try. I loaded all my weight-sorted premium castings a few weeks ago but have some culls left over. I loaded 18 random ones from the cull pile and shot a 1-3/8" 9-shot group with them last weekend (suppressor cooling jacket test) so they ought to do at least that well for you.

 

[wquiles]

I can't send you the powder but can send some bullets. Send me a PM with your address and I'll ship out some to try. I loaded all my weight-sorted premium castings a few weeks ago but have some culls left over. I loaded 18 random ones from the cull pile and shot a 1-3/8" 9-shot group with them last weekend (suppressor cooling jacket test) so they ought to do at least that well for you.

That would be great - thanks. PM incoming ....

 

[wquiles]

Ian, got the package - thank you. I plan on making some rounds using both blue and red ones tomorrow and then go to the range with my daughter, but today I started with the reamer:

Several years ago I had an idea for a die, and bought a die blank with a 30 cal pilot hole:

As it turns out, the ID was right at .299-ish":

Turn chuck by hand, and proceed very slowly with lots of heavy duty cutting oil ...

Cut and clean, many times ....

I got to about here:

I am not done polishing, but I started:

 

[wquiles]

Entry ID went from .299" to about .314" to .315" (now tapered, of course, so hard to measure exactly):

Still could use additional polishing - any tips on how you polished yours?

My bullets sized .3085" which were nose sized with my prototype nose-sizing die go completely in:

But your blue ones, PC coated of course, go up to about here:

Does that mean I need to keep reaming deeper, or is this as expected?

Will

 

[Ian]

With that reamer I would poke it in all the way, but make dang sure your tailstock is aligned dead-center of the chuck or it will wallow out the hole to a taper.

That reamer is tapered at the front, has a parallel section for the bullet driving bands, and if I remember correctly also has a little taper again toward the root for the entrance. Check the cutting edge carefully with a mic and you can see the shape it makes. If your tailstock is on center, the driving band portion should only be about .3085-.309" or so which will effectively size a .311" bullet down under .310".

Ok, it's kind of difficult to describe my bush league polishing process but it involves about 1K rpm spindle speed, a 1/4" birch dowel, and a worn out strip of 400-grit emery paper spiraled around the dowel to form a slight taper. Oil the paper with light penetrating oil and poke it in there until it almost binds up, keep it moving, give it some side pressure to keep the end working deep in the die, work fast and don't over-do it.

 

[Ian]

The bullets I sent have all been sized in a die cut with that reamer and were pushed in almost 1/8" below flush to get the final nose and body dimensions. The gas check springs back (or my die is tapered) a few tenths larger than the driving bands. If I were to put a bullet back in the die there is still considerable force required to get it in and out again. Try lubing the die and sizing some of your bullets to see what you h3ace right now before modifying the die further.

Also...pre-sizing the body if the bullet to .310" with a push-through (Lee) die makes the trip through the truing/uniforming die a lot easier!

 

[wquiles]

OK, was able to continue work today:

Polished a little, but need more:

Now just finger pressure, I can get the blue bullet to about here:

The Lee 312-155 does not need nose sizing for me, but I will try it soon


By the way, tomorrow morning I will be trying your blue and red pills (remember from the movie the Matrix?) - what was your COL? Of course I have to try in my barrel, but I wanted to have that reference data point.

I have been playing with QuickLoad and for your blue/red pills, since they are slightly heavier (around 174gr vs 170gr for my Lee's), so it looks like I might start 0.5gr lower with Varget to see how it works

Will

 

[Ian]

2.700". I like round numbers

Don't obsess over polishing, I think its plenty good. Coat the inside with sizing wax and give it a go. The slight accuracy advantage I see from using the die seems to stem from squaring the base, bands, and nose all together in the same die, you could also do this with your Lee bullets. The other advantage is truing and possibly reshaping the noses of the bullets for the autoloader so that parting lines and bumps/globs if powder coat don't interfere with chambering.

 

[wquiles]

OK, my rifle seems to do a little better with your bullets than mine, which is what I expected as I know my cast bullets are not yet "there"

Tried first the 2.700":

But those were too long for my rifle:

I went down to 2.686", and the bolt closed and dummy rounds ejected fine, so perhaps with more experimentation I can get closer to 2.690+.


Then went to the range - like in the movie the Matrix, I got blue pills and red pills

I know a group of 5x for every 0.5gr is not the best, but it was a start. This was with 41.0gr Varget:

41.5gr Varget (top hole has two shots!):

42.0gr - Left most was the first shot, and I blame the shooter for that one. I concentrated better/more consistent for the other 4x:

And that above was the limit of that bullet/alloy/PC/etc. as with 42.5gr the group (here in the middle of the other 4x targets) more than doubled in size:

 

[wquiles]

So it looks like somewhere in the 41.5gr and 42.0gr Varget I might have a good 100yard node. Not bad for magazine fed semi-auto rifle


popper - got the care package at the range. Thank you sir. I will report once I get to try them out

You guys in this forum are great! Thank you so much

Will

 

[Ian]

Cool. I think we have a winner, at least you know what the rifle can do with cast bullets and 14-15 bhn alloy. Did you chronograph any of the loads?

Not chambering 2.700" is why I size the noses, but it looks like your rifle needs more HV shooting to be able to chamber them or a little tighter on the nose-sizing part of the die. I'm not sure your .299" die will do it, but the Lee bullet has a smaller ogive anyway.

I don't see any scuffing on the front driving band at all, maybe your rifle's throat entrance is bigger than mine? Might need a slightly larger driving diameter?

I ran the numbers in QL and your 42.5 grain load is bumping over 47,000 psi (similar to my 35.5 grain load of RX-7 which was nearly 50K and held groups out to 400 yards) and should be clocking about 2450 fps with the can. The RX-7 delivers 2,000 psi less muzzle pressure, though (20%) so there's something to think about.