Testing the 30XCB

[Bjornb]

Went to the range this morning, to test Big Bertha, the target rifle rechambered into 30x57 (30XCB) by Tim Malcolm. I picked up the rifle from Tim in Arkansas about a week ago, and I've been busy prepping brass and loading rounds since then. My ammo for today was as follows:
168 Hornady A-max, 42.4 grs. IMR4895, 10 pcs.
155 SMK Palma, moly coated, 44 grs. IMR 4895, 10 pcs.
160 grs. Accurate 31-160G, cast, sized and lubed by Tim, 43 grs. AA4350 (10), 44 grs. AA4350 (10)
155 grs. Lyman 311466DX, lino/scrap, sized .309, Lars CR lube, alu. gas checks, 10 each of 43, 44 and 45 grs. AA4350.
All shooting was done from bench, at 100 yards, using front rest and rear sand bag. I also used my rudimentary Chrony Beta to record velocity.

The A-max bullets that had shot well for Tim during his testing did not shoot well for me. After managing a 4-inch group (10 shots) I was about ready to pack it in from depression. The rifle was rock steady, and there was no wind, so I had no excuses.
Shifting to the Palma bullets changed things around a bit. At least it clearly showed that Tim knows how to build a rifle:

Average MV was 2745 fps, with an extreme spread of 35. Pretty good so far.

However, this is when it started going downhill. All the 4350 loads went all over the place. I'm not even bothering with pictures, it was ugly.
Velocities recorded were from 2151 fps with the Accurate bullet (43 grs.) to as high as 2445 fps with the 311466 and 45 grains of powder.
I even let one of my RSO buddies sit down for a 5-shot string (he's a competitive F-class shooter) just to make sure I wasn't getting Parkinson's or something similar. His grouping was every bit as terrible as mine. We are talking 8 inches or more here. Not worth measuring.
So, just to sum up some of the possible issues:
1. I was fireforming my brass
2. Cases and bullets were not weighed or segregated
3. My bullet alloy is definitely not high quality stuff

These are just observations, not excuses. I'm going back to the drawing board that will include the new NOE bullet developed by Tim and Larry for this cartridge.
I'll be casting these from real Lyman #2 alloy, and lubing with Lars 2500+ as per Larry's suggestions. I used CCI BR-2 primers for all the above loads. I'll be switching to Winchester LR primers for the future, since that's what the other participants in the testing will be using, and it's also a primer I have a good supply of (with the same batch number).
It was a very interesting outing, and I'll continue to post my rifle's performance when I have something to report.
Bjorn

[Bjornb]

Yup, Bjorn, you're learning the same way I did......if you're going to dance you've got to pay the band. In this dance that means quality everything especially the cast bullets and the alloy not to mention everything else. She's a beautiful dance partner and sure can swing once you quit stepping on her toes........just remember, once that bullet comes out of that muzzle balance is everything..........if that bullet isn't balanced she steps on your toes..........

Larry Gibson

Very true. This is my first foray into loading for "real accuracy", and a lot of the old habits (that die hard) have to be changed. I have for a long time been very happy with Ed Harris' 16 grains of 2400, and with shooting milsurp rifles of average and sometimes even of good quality. It will take some time and some stumbles but I'm sure enjoying the journey!

[Bjornb]

OK, so I took Big Bertha back to the range today to see if she (and I) could "Dance With The Stars". I came a little better prepared this time, both Larry, Tim and Sgt. Mike were consulted on the various aspects of how to make the 30XCB shoot. I received a 4-cavity brass 30XCB 165 gr. mould from Al Nelson, and after mixing Lyman #2 alloy in the Lee bottom pour I was casting bullets. The bottom pour bullets didn't impress me however; they didn't have a nice consistent look, so after about 150 bullets i switched to a regular Lee pot and a Lyman ladle. This immediately changed the appearance of the bullets to the better, and about 250 were cast up. I then weighed and sorted them; they weighed between 158.2 and 159.6 grains with a decent bell curve in the middle. Tim told me it wasn't perfect and that the curve showed I was running the pot too hot (745 with a PID), and I'll change that next casting session. But, I went ahead and loaded 116 rounds for this test. That was the number of cases left to fireform from the first outing. I loaded as follows:

30 grs. IMR4895 w/dacron and second sortiment bullets (bottom pour):16
43 grs. AA4350:10
44 grs. AA4350:10
45 grs. AA4350:10
50 grs. H4831SC:10
51 grs. H4831SC:10

The remaining 50 were loaded over 16 grs. 2400; I knew I'd be running short on time at the range and wanted to get all the brass fireformed.
Primers were Winchester LR, Lube was Lars 2500+, gas checks were Hornady. Lubed and gas checked in one step in a Lyman 4500 with a .311 H&I die.
There was no issue chambering with the bullets having dropped at .3105-.311.
All shots were taken at 100 yards.

First I shot the IMR4895 loads. Except for the first from a cold barrel, they settled in nicely:

Then the last 6 I had left:

These were reject bullets from the bottom pour session, so I was starting to feel pretty good about the rifle. The first of these loads measured 2100 FPS on the chronograph, and then I got an error message on the second shot (couldn't reset my cheapo Chrony with the line being hot), so no further MV reading were taken with this load.
I then started shooting the AA4350 loads, and I'll just post the pictures here:



Larry had commented in a PM that he thought my 4350 loads were a little on the light side, and these groups indicate that he's right about that. Next range visit I'll keep increasing with the AA4350 until groups fall apart.
Finally I shot 20 rounds of the H4831SC; the first group stay reasonably together, but with 51 grains (case takes 52-53 max.), it fell apart pretty badly:


All in all a very good outing, I'll keep on truckin' until next time.
Bjorn

[MBTcustom]

I have to say, Picture #2 is by far the best group I have ever seen with cast lead anywhere close to that speed. Good Lord, you could shoot aspirins off a plank at 100 yards with that load.

[Bjornb]

Now that is more like it! Very good indeed! The cartridge/rifle/NOE bullet are definitely bearing fruit. That H4831SC load that fell apart just may need a bit better weight selection. It is right about the velocity/RPM where my 14" twist barrel's accuracy falls apart also. More testing is needed......you won't mind that, eh?

Larry Gibson

I can be talked into some more trigger time.....you know Larry, Bruno's in Phoenix has 1 in 18 twist Kriegers in stock.......it's tempting to go for 3K.
....Jokes aside, I'll be shooting at a larger range later this month, my goal is to have tested enough loads that I can bring some to the 200 and 300 yard ranges. Unfortunately I live in a Metropolis cesspool that serves 1.8 million (Broward County) with ONE 100-yard rifle range. It's a disgrace but not likely to improve anytime soon.

[MostlyLeverGuns]

On your first outing, did you shoot the moly 155's before the lead?. Occasionally, moly can cause difficulty if not cleaned out before boolits. You probably cleaned the bore before the next batch?

[Bjornb]

On your first outing, did you shoot the moly 155's before the lead?. Occasionally, moly can cause difficulty if not cleaned out before boolits. You probably cleaned the bore before the next batch?

Yes I shot the moly before the lead, and no I did NOT clean the bore between batches. Funny you should bring it up, Sgt. Mike commented on the same issue when I told him I was planning to load the molys. He had previous experience where the moly coating caused problems for later non-moly loads. It could account for some of the bad shooting, but I choose to believe that the main culprit was poor bullet quality, sizing the bullets too small (.309) and also possibly poor lube choice. After all we're only talking 10 moly-coated bullets. But who knows....

[Bjornb]

Miller formula gives that bullet a good 1.4 for stability (recommended number for full stability) at 2600 fps with an 18" twist..........standard '06 may be the better case for pushing to 3,000 fps to keep the psi manageable. Let's see where we get with the 30x57 in the 16" twist barrel. At 3000 fps the RPM is 135,000 which is where we seem to be topping out with the 14" twist barrels. I'll have the action length with the VZ24 action for the chamber to be reamed deeper all the way to '06 if needed. That's one of the concepts behind the 30x57 using an '06 reamer is you can adjust the case capacity from .308W to the '06 case capacity and anything in between depending on the case capacity needed for the velocity/barrel twist/bullet weight. Some are failing to comprehend that concept and the other design concepts when comparing the 30x57 (30 XCB) to other similar cartridges.

Back to your thoughts......3000 fps may be entirely possible and we could just jump ahead but since the 16" twist is on order lets see what it does. The 18" twist is getting on the borderline of stability with the 165 gr bullet unless it is run at full throttle. Now with the stubby 311465 Loverin 122 gr bullet.........hmmmmmmm

Larry Gibson

It will also be interesting to see if you can get good results with the 150 gr. LBT mould. It has a nose/body design similar to the NOE, but is considerably shorter.

[tomme boy]

I have seen just switching from IMR to Hodgdon powders you had to shoot about 5-10 shots to recondition the bore. I think ANY change of components is going to matter if you are after the best possible groups.

[Bjornb]

Yes, this project is only in its infancy and lots of test shooting lies ahead (and that's what I love about it!). I'll be trying out several of the "slower" rifle powders (and then Larry will get his rifle and I can shamelessly copy his loads). I've been using QuickLoad data for the Krag 30-40 and the RCBS 165 SIL bullet to approximate speeds and pressures in the XCB. The loads I shot today were very close in velocity.

[runfiverun]

never mind the moly coating.
I use moly lube for the HV loads.
if someone can show me how moisture will penetrate a moly [or cast boolit lubed] coating and attack a barrel i'll scrub it out of my AR-30, 6-H target, 30X284, and my Armalite M-15 N.M. rifles right now..

[Bjornb]

No problem. The Lilja FAQ link was an interesting read.

[runfiverun]

sorry for the drift also.
I worried about the moly thing for 20-25 years then gave up, it could just be the climate differences we all face [shrug]

anyway, going 2 steps slower than slow for jacketed is generally a good place to start looking for cast velocity.

[taco650]

Bjornb,

Those are some promising groups!

[2wheelDuke]

I can be talked into some more trigger time.....you know Larry, Bruno's in Phoenix has 1 in 18 twist Kriegers in stock.......it's tempting to go for 3K.
....Jokes aside, I'll be shooting at a larger range later this month, my goal is to have tested enough loads that I can bring some to the 200 and 300 yard ranges. Unfortunately I live in a Metropolis cesspool that serves 1.8 million (Broward County) with ONE 100-yard rifle range. It's a disgrace but not likely to improve anytime soon.

It's nice to see somebody shares my misery in having to deal with Markham Park. Markham makes a road trip up 27 to Hendry County not seem so bad.

[Bjornb]

Yep, Markham Park it is, and I spent some time of today loading for tomorrow's trip to the range. I'm building on last week's loads, increasing the amount of AA4350. 45,46,47 and 48 are all loaded. The only change I have made is heat treating the NOE bullets at 460 degrees for 40 minutes. I don't have a reliable hardness tester, so I can't really say if it's made a difference. I also seated the gas checks in a separate operation on the 4500, it looks like they are easier to get perfectly square that way. The cases are now fireformed and have been neck sized in a "stock" Redding 30-06 N/S die cut short by Goodsteel. Time will tell if it becomes necessary to get a bushing style die. The loaded rounds measure .3375-.338, which makes them sit very tight in the chamber. I have a .310 H&I die coming Monday (sizing .311 now), that may just be what gives the perfect fit. I see no reason to turn the necks any further; they measure .0125 now and that's supposed to be just right according to my intel. I'll check back in when there's something to report.

[MBTcustom]

Sounds very copacetic Bjornb. Good luck!

[Bjornb]

OK this will be short & sweet (maybe): Went to the range today, got most of my shooting done before a thunderstorm gave us the "Lightning Warning" and firing was halted.
When I finally collected my target it was disintegrating, so I won't bore anybody with snapshots. I had loaded the NOE bullet, heat treated since last outing, over these charges of AA4350: 44,45,46,47 and 48. Avg. MVs were, respectively, 2381,2470,2495,2588 and 2573. 10 shots fired of each. Both the 44,45 and 46 gr. loads stayed below 2 MOA, just like the lighter loads had done previously, but the 47 and 48 grain loads started to scatter badly. Additionally, all avg. velocities were lower this week compared to last, and the 48 grain charge was slower than the 47.
I had to drop the rifle at my shop without inspecting her closely, I need to see if there was leading. I don't really know what else could have caused the speed decrease.
One thing had changed: All brass this outing was fireformed, and neck sized in a Redding NS die. With the bullets loaded as cast (close to .311), it made for several tight chamberings. Sizing down to .310 should relieve that problem somewhat.

I had also loaded some jacketed rounds to establish some baselines. However, I ran into some unexpected problems here. The fired cases were very difficult to extract (loads were definitely not very high pressure), and the cases had to be tapped out. Goodsteel speculates that he fabricated the extractor with not enough "bite" on the extractor groove (to ease chambering). I tend to agree, since the cases didn't need much persuasion to be loosened. The jacketed loads were 125 SMKs over H335 and 150 SMKs over IMR4895, pretty much 308 Win. loads from the book.
I'm taking a trip to Arkansas this coming week, so I'll bring Bertha over to Goodsteel's for an inspection of the extractor. More to follow when she's back on the firing line.

[Bjornb]

Yeah I have gone back and tried to analyze what happened. A different chronograph was used (same model Chrony but with remote control). That could account for the lower velocities across the board, but it still leaves the discrepancies between the individual charges. I weigh all my charges on an RCBS Chargemaster 1500. It could be off, I'll check it with control weights. Maybe it's time to break out the old RCBS powder measure and a beam scale.
I'll be casting some more NOE bullets this week, using certified Hardball alloy from Roto. Just to take another variable off the table. I couldn't be 100% sure my linotype was exactly as advertised, thus I didn't trust that my alloy was really Lyman #2.

[runfiverun]

sometimes a powder just flatlines when it's near a peak.

I'd really like to see you go to a slower powder than 4350.
rl-19 is going to be my starting point, and rl-22 is on my second step list.