Arsenal 311- 176 PB

[Spindrift]

I had the opportunity to shoot this a little today. I have a 4- cavity PB mould. I shoot a lot of cast bullet loads in the 16-1800fps ballpark in my .30- cal rifles. These loads are easy on the shoulder, yet are more resistant to wind drift at my typical 100m distance than low-node PB lubed bullet loads. PC allows me to drive PB bullets in this velocity window, and it saves me the labour of making/ installing gas checks.

Previously, I’ve found PB/PC bullets in this weight range tend to shoot well with 20grs Vihta N110 in the .30-06. I loaded 15 rounds, with bullets that «survived» the mould break-in. I admit to some leniency in the bullet sorting process, there were some minor flaws.

I fired 3 5-shot groups from a bench using my Scultz& Larsen .30-06 hunting rifle, wearing a 2.2-9x scope, and a suppressor. It resulted in 3 nice groups, averaging 1MOA. I’ll run them over the Magnetospeed later, should be about 1700 fps.
I’m very happy so far, good start!

 

[Spindrift]

I had to adjust to some construction work on the range today, and only shot at 80m. I tried some slower powders with the Arsenal 311-176, still powder coated plain base bullets, sized .310. The rifle was my trusted Scultz & Larsen 30-06 with 1:10 ROT. I chronied some loads, as well.

First, I shot some rejects; bullets with various minor defects with 20 grs N110 (1725 fps). One very nice group, and one tat opened up to about 1,5 MOA. Still, not to shabby for plain based rejects at 1725 fps!



I had some rounds loaded with Norma 200, 26-28 grs. I expected 27 grs to be the sweet spot, and 28grs to be a little to much. But actually, accuracy improved with increasing load weights, 28 grs (1912 fps) being the most accurate. Not quite as accurate as 20 grs N110, though.



I also tried Vectan Tu-3000, which has a listed burning rate in the 4895- range. I’ve tried 30grs earlier, which burned well- but gave mediocre accuracy. Today, I tried 29 grs which gave good accuracy, 1755 fps, but left some unburned kernels



This bullet is really growing on me. It clearly is an excellent match with this particular rifle. It remains to be seen wether it performs similarily with other rifles.

Edit: spell check. Large fingers, small tablet.

 

[Wasalmonslayer]

Not to shabby glad it is working so well for you

 

[STIHL]

Very nice shooting, that is a nice bullet design. I wonder is the vectan powder just too slow to completely burn under the small amount of pressure generated by such a reduced load? Just my curiosity stirring I think.

 

[Spindrift]

Thanks, guys!
@STIHL , yes that seems to be what is happening.
My impression is, Vectan Tubal-3000 has pressure requirements (for complete burn) somewhat higher than expected, relative to the burn rate. With this bullet, the pressure where complete combustion is achieved is just above the tolerance of the rifle/bullet system. A more tolerant bullet (GC/PC) could take it with no problems. I have some coated bullets with a plain base gas check under the coat; when they have matured, I’ll see if they can take the 30grs load.

I have found many accurate loads with this powder, even though some unburned kernels remain. But since I mostly shoot suppressed guns, the idea of accumulating unburned powder in the suppressor does not appeal to me.

This powder is the reason I have aquired some Dacron. It would seem to be a textbook example of a powder that could benefit from a powder positioning agent. Or; it would be a textbook example, if such a textbook excisted. The best explanation I have found, is in the basement articles by @Ian . One day, I’ll try som Tubal-3000 loads with Dacron. If nothing else, just to deepen my understanding of this powder (and internal ballistics).

 

[STIHL]

That might actually work. Would be interesting to know. I’ve got a 30-06 here that really isn’t a good deer rifle, it may become a cast bullet rifle in the near future. If I can’t find the jacketed load it likes. Had one that shot great, then it went to crap. Barrel may have broke in and just need a rework of the load, but I may try some cast through it too.

 

[Ben]

One very nice group, and one that opened up to about 1.5 MOA. Still, not to shabby for plain based rejects at 1725 fps!



I could learn to like that load.
Ben

 

[Spindrift]

@STIHL , sounds like a nice plan. The 30-06 is an excellent cartridge for cast bullets.

If the accuracy of your rifle has deteriorated with no clear explanation, then shooting some low recoil loads with cast bullets might help with the diagnostics. If it has poor accuracy with full power loads, but shoot low power (and recoil) loads well- it’s probably a bedding issue.

I actually have a similar situation. A new-to-me Browning X-bolt 30-06 that has mediocre accuracy with factory bullets. Not horrible, but I expect better than 1,5-2 MOA from such a rifle. I’ve found no obvious issues when dismantling the rifle, and the bedding seems sound. I’ll try some cast bullet loads next. If they won’t shoot either, it’s probably going to the doctor!

 

[Spindrift]

Last range trip, I was excited to see that accuracy was still good with 28 grs Norma 200 at 1912 fps. I had only 11 mature bullets left (more to come!). Today, I chose to test one bullet with the 20grs N110/1725fps for expansion. Then shoot 2 5-shot groups with 29-30grs Norma 200, to see if I could retain decent accuracy at this level. One 5-shot group is not to be considered descriptive of accuracy, of course. Just a probe, so far.

Usually, I test expansion using water filled containers. But all available containers had holes in them! So I packed a half gallon milk carton with news print, and saturated with water. This will not stop the bullet, of course, bit I get a visual impression of the bullet’s behaviour in the first 4 inches of travel through wet paper.
This is the exit hole, my thumb on the left for reference. Seems to behave pretty civilized at 1725 fps. A little more cavitation would be nice, maybe.



5 shots with 29grs Norma 200. The «clover leaf» actually consist of 4 holes. 31mm c-c. Not chronoed yet, but probably around 2000fps



I was quite excited how the 30grs Norma 200 load would work. It worked fine, 33mm c-c is about 1,1 MOA at 100m. I’ll chrony it later, should be 2050+fps.



I’m pinching my arm over here. Close to MOA accuracy with a plain base, scrap alloy bullet with muzzle velocity more than 2000fps, using a light weight hunting rifle.....
I love this bullet!

 

[STIHL]

That’s some good shooting. I had actually looked at that mold again yesterday, thought about doing a 50/50 mold, but more ive thought on it think I’m just going to do a plain base and if Check is needed I’ll buy another. This is going to be a next year project when I have some time, after deer season is over.

 

[Spindrift]

@STIHL , I’ve only shot the bullet in this one rifle, but it wouldn’t surprise me if it shoots well in other rifles as well.

For hunting, it is probably not helpful to push this bullet faster than 2000-something fps. It would probably increase the risk of overexpansion and bullet failure with this WFN. And when you can reach the terminal ballistic «sweet spot» with powder coated plain base, there’s not much use for a GC, is there?

Good luck with your deer season!

 

[STIHL]

Thank you sir. Weather is going to be right this weekend im looking forward to getting out and doing some scouting around this weekend.

That is a really nice looking bullet and it lends itself to looking like a really nice shooting bullet in about anything I'm thinking anyway.

 

[Spindrift]

I’ll be shooting it in various other rifles, eventually. It will be interesting to see if the nose design is as adaptive to different throats as I think. But right now, I’ll have to pursue this load a bit further, just to see where the failure point of this PB/PC bullet really is. It is already offering performance similar to a max. load with 170grs jacketed in 30/30.

 

[STIHL]

a 30-30 with 1 170 RN jacket bullet hits hard at a 100 yards, it knocks the 12 inch plate around pretty good. Ive got to get on my cast rifle projects and get started I have quite a few to check right now and then find my final size got a couple 30 cal HP to try out and a LEE 170. I was wanting to buy me a new Savage Axis 308 for a cast bullet rifle only, but I may just clean the 06 I have and try it out for now I have a bunch of brass ready to go for it too. makes too much sense not too.

 

[Ian]

Great work, Spindrift!

 

[Spindrift]

Thanks, Ian!
Stihl, that 30-06 might be an excellent cast bullet shooter. Every reason to give it a try!

 

[Spindrift]

Testing so far has been with my «default» alloy, nuclear medicine lead with a hint of tin and BHN around 14.
But then I ran out of ingots, and cast some bullets with tin-starved range scrap in the BHN 10-12 range. Powder coated, sized .310. Matured 4 weeks after coating.

Last time, with my slightly harder alloy, I found good accuracy all the way to the top load, using 30grs of Norma 200. With this softer alloy, tolerance might be different. I loaded a little ladder with 29-30-31 grs. I anticipated the 29grs load would give the best balance regarding accuracy and terminal performance, and loaded some extra cartridges with this load. I also shot some bullets over the magnetospeed, and into a 4- inch block of newsprint, saturated with water. An aggressive pumpkin also showed up at the range.

3 shots at 20m into newsprint at 20m from top to bottom:
29grs (2000fps)
30grs (2057fps)
31grs (2090 fps)
Notice the blow back in the entry of the bottom (31 grs) load



The same block, viewed from the exit side. The photo is a little misleading. The dramatic cavitation of the 31grs load displaced the medium, making the exit holes of the other loads appear smaller. The 29 grs load made a nice, thumb-sized hole, the 30grs load a noticable larger hole. And the 31 grs load- well, you can see for yourself



I shot the 29grs load at the same medium at 100m, and also shot the pumpkin. I don’t regard pumpkins as a valid expansion medium, but.... I couldn’t think of a better use for it.



Accuracy with these softer bullets was not as good as with my other alloy.
29 grs produced a 1,5 MOA 5-shot group at 100m
30 grs gave the worst group yet, almost 3 MOA
31 grs gave (for some reason) a 1,5MOA group that might have been a fluke.

Translating such simplistic wet-pack shooting into terminal performance on game is not straight forward. Game animals have tough skin, and bones. I will assume, for now, that the 29grs load is the better balanced load with this alloy.

Next time, I’ll shoot some more bullets with this softer alloy. I have some bullets prepared with a plain-base GC under the coat. It will be interesting to see if this will increase the tolerance in this load window, which seems to be on the limit of tolerance for the PC-only bullets with the softer alloy.

 

[Spindrift]

Another shooting with the soft BHN 10-12 alloy, and Norma 200, 29-31 grs. The reason I found this combination interesting, is the fact that accuracy is breaking down at this load level, with the soft bullets. I wanted to see if the addition of a plain base GC would help.

I make PBGC from beverage cans, using a Pat Marlin checkmaker. Previously, I’ve found such checks to expand the range of useful loads with lubed, PB bullets into the 16-1800 fps range. With PC bullets, however, I’ve not found a similar increase in tolerance.

Last winter, I shot a bunch of (among other things) coated PBGC bullets, into a field of snow. In the spring, I could retrieve a handful or two of bullets. Quite a lot of the PBGC, PC bullets had lost the check, despite absence of any other kind of distortion to the shape of the bullet.
Thus, adding a PBGC to these PC bullets also adds a variable; does the check fall of, or not?

What I found today, was that the PBGC had no effect on the accuracy, which was consistenly worse than with my BHN 14 bullets.
This is consistent with my earlier findings with other bullets; in the presence of PC, adding a PBGC is not helpful in any way. Lubed PB bullets is another matter!

 

[Ian]

Interesting the PB gas check didn't improve the accuracy of the soft alloy when powder-coated. Have you checked your moderators for evidence of check fragments inside?

My speculation here is that the accurate velocity limit of your alloy is a matter of how much pressure the bullet base edge can withstand before collapsing, and not the alloy's ability to hold the lands as in the case of the uncoated bullets. PB checks don't add much strength to the bullet base, just the surface itself. The MP 30-180 Silhouette bullet will withstand 2600 fps at 14 bhn (wheelweights with a little tin added, my wheelweight metal has a lot of trace stuff in it that makes it harder than normal) with a copper gas check, but 12 BHN doubles group size.

All of these systems have limits, half the fun is finding out where they are and investigating the causes.

 

[Spindrift]

Have you checked your moderators for evidence of check fragments inside?

Well, I have now..... excellent idea! No fragments in the moderator, though

All of these systems have limits, half the fun is finding out where they are and investigating the causes.

Couldn’t agree more!