Testing the 30XCB

[frnkeore]

I'm not sure why a experianced, experimenter would choose to work with a defective mold/bullet. If there isn't anything between the mold faces, holding the mold open, I can only say that the mold is defective. You need to send the mold back to Al and tell him your problem. There was a option that could be purchased of a oversize bullet. Did you get one of those by mistake? If you test my bullet, please do it with a properly droped bullet.

Sizing a bullet from .313 to .310, ruins it. Bjorn states that sizing the XCB approximently .0015 degrades it accuracy a lot. At .313, the ELCO ogive is to big to fit the leade, properly, sizing it .003 also, lengthens it (the alloy got to go somewhere, right?) and can severly distort the bullet in doing so. Based on the as cast size, the GC should not begin to fit w/o either expanding the GC or shearing the GC shank. Note the GC on my bullet is .2842 when the bullet is .3098. This bullet is made to be shot, as cast, at no larger than .3105. My blocks are brass and aluminum blocks should cast about .3102 but, no larger than .3105.

I can't explain why your bullet would cast .313 and weigh less?????? Unless it is short.

I cast 10 bullets tonight, using alloy from a lino ingot at 780 deg. with the following results:

.3098

GC weighs 4.2 gr. Total bullet weight 165.6 - 165.9

Total OAL will be 1.076 w/GC (.017 GC thickness)

GC shank = .2842

Frank

[MBTcustom]

Frank, Larry did ask you to send him a sample of your bullets/mold, and you told him to get one from NOE.
Did he not do exactly as you said?

The good news is, I believe Bjorn is going to do a similar test in his rifle very soon. He also bought a mold from NOE as recommended, and he also will post results here in open forum with chronograph readings, and ten shot groups. If it passes this very first hurtle, it will probably be tested more extensively at longer ranges as well side by side with control groups from known bullets (so far, only the 311466 and the 30 XCB have been properly documented as being solid HV performers across the board). Maybe Larry's rifle just didn't like the design.

Regardless, I wouldn't be too disappointed if it does not work well at the speeds the XCBs are being shot, and with the 10 shot groups. Very few bullets can do that, which is why I felt compelled to design the XCB bullet in the first place. Heck the XCB bullet can't do it unless very strict protocall is followed in the casting, checking, sizing and lubing of the bullets, as well as an adherence to specific "excellent alloys" (see my thread in cast boolits titled "consistency applied").
We'll see what Bjorn gets.

[Larry Gibson]

There is nothing "defective" about the NOE 309-169-FN 4 cavity mould I was loaned for use in this test. Prior to use I carefully inspected the mould. The blocks aligned perfectly and closed completely. I also visually check block closure during casting to ensure nothing has accumulated on the face of the blocks to prevent complete closure. The blocks not closing also produce out of round bullets and usually a large weight variation. In the case of the bullets I cast with this NOE mould the bullets are very much round and I could discern no difference in weight or size variation cavity to cavity. The GC shanks were .286 (the same as with the 30 XCB and 311466 shanks) and there was no shank shearing as the uniformed (MBT GC uniforming tool) Hornady GCs fit the shanks perfectly.

Simply put the NOE mould cast very beautiful looking and uniform bullets.

A check of the design specification drawing for the NOE 309-169-FN bullet shows it is designed around wheel weight alloy and should as cast out at .309+ diameter with that alloy. As expected when COWWs + 2% tin, Lyman #2 or linotype alloys are used in a mould cut for straight WWs the as cast diameter of a .30 caliber bullet will be as much as .0025 - .003 larger. That was exactly the case here. The nominal weight of a bullet cast linotype vs WWs will also be lighter. The mould design using WWs is supposed to give a fully dressed weight +/- of 169 gr. Cast of linotype the bullets from this mould weighed 164.5 gr fully dressed +/- .2 gr. That is well within the variation expected considering minor variations in alloys of the same composition. Since I see absolutely nothing wrong or out of specification and there is no "problem" with this mould as it casts excellent bullets I will not recommend to the owner it be sent back to Al at NOE. If the mould were mine I would not send it back and waste Al's time. The mould is excellent and well within the design specifications on the drawing.

As far as the bullet becoming distorted from sizing and causing the kind of inaccuracy I found with this bullet I have to say I have never found that amount of inaccuracy before. A small amount yes but 7 - 13+ moa worth of inaccuracy? As an example; I have 3 Lyman 311466 moulds. The 2 cavity is an older one cut to original specs and it also drops the bullets as cast of linotype at .314+ When sized down to .311 and then shot in the .3085 Palma barrel it manages consistent 1 1/2 - 2 moa accuracy at 2550 - 2700 fps. The 4 cavity Lyman is a 311466U and it drops as cast linotype alloy bullets right at .311. That bullet with the same loads at the same velocities holds moa - 1 1/2 moa accuracy at the same 2550 - 2700 fps. Both again with the same components and used in the same Palma .308W rifle with 14" twist.

One could say, I suppose, the bullet did not fit the particular throat of a rifle. In this test only one of the bullets (30 XCB) fit the throat/leade of only one of the rifles, the 30x60 XCB. All of the bullets were sized to fit the throats of the rifles. I tested this bullet in two rifles; the Palma .308W with 14" twist and in the 30x60 XCB rifle with a 16" twist and the longer neck. Given the long throat of the .308W the 309-169-FNs (ELCO) sized at .311 were a very good fit and basically fit as well in the case neck and throat as did the 311466 and the 30 XCB. The throat of that chamber is as was cut at the Shultz & Larson factory. It worked fine with the 311466 and the 30 XCB but not with the ELCO bullet. The throat of the 30x60 chamber is cut for a .310 sized bullet and both the 311466 and the 30 XCB shot very well at HV in it. The ELCO bullet did not. Are we to thus believe the leade not matching the ELCO bullet was the cause of the extreme inaccuracy ( 7 - 13+ moa) as compared to the other two bullets.....really?

As I was very delighted with the looks of this NOE 309-169-FN bullet and did indeed have high hopes for it in the 14" twist Palma rifle at HV for longer range shooting to say I was disappointed in the total lack of accuracy is a gross understatement. I should probably note that I was tempted to use the M43 Oehler as to also measure the actual BC of the ELCO bullet at HV. However, long experience hard learned through shot screens has given me the insight to use my Oehler M35P first to measure velocity, accuracy and point of impact at 100 yards first. Fortunately I did that with the above test because had I not the inaccuracy of the ELCO bullet would have proved disastrous to the down range sky screens in front of the 100 yard target. We do "live and learn".

I do also eagerly await the results of Bjorn's test in his 14" twist 30 XCB rifle of this bullet. Perhaps this bullet just didn't like either of the two rifles or cartridges I used in this test(?). In the mean time I will work up some loads with this ELCO bullet in a M70 30-06 with a 10" twist 24" barrel and see how they perform from 1700 - perhaps 2400 fps. Thus the testing continues.

Larry Gibson

[popper]

Tim - we got pretty good with tygon tubing and a doggie bowel, 150 yds at the third floor girls dorm windows. Gals even enjoyed volunteering as targets - until we got to putting them through the windows.

[frnkeore]

As designer of this bullet, the point remains that it WAS out of spec!!!! The bullet that you shot was not designed to shoot in anything that I intended for it. If it was the oversize version, it's NOT my bullet. If it wasn't, it was a DEFECTIVE mold! My bullet is designed to shoot as cast or no more than .001 sizing. If you think that the lino caused it to cast .313, then the XCB should cast .314 or larger and your test should have been with the XCB and the 466 sized from .313 down to .310. Ask Borjn what happens to the XCB when it resized, please, he's done it.

Send it back to Al, he replaced a undersize 311299 for me w/o problem and was happy to do it.

Tim, is there some requirement that I supply molds to people to test? If so, the reverse should apply and please send me one of your rifles that I might test my bullet in your's or Larry's or Borjn's rifle. I didn't see Larry offering me his rifle to test my bullet. I will offer him the same, pay the return shipping and I won't hurt his rifle. Fair enough?

Now, my bullet was never designed to shoot at velocitys over "Match Velocitys" (approx 2000 - 2200) but, to test it out of spec at ANY velocity is absurd. If you want to test the .313 in a 303 Brit, at normal velocitys, I would would be interested in those results if, done with a open mind.

Frank

[MBTcustom]

As designer of this bullet, the point remains that it WAS out of spec!!!! The bullet that you shot was not designed to shoot in anything that I intended for it. If it was the oversize version, it's NOT my bullet. If it wasn't, it was a DEFECTIVE mold! My bullet is designed to shoot as cast or no more than .001 sizing. If you think that the lino caused it to cast .313, then the XCB should cast .314 or larger and your test should have been with the XCB and the 466 sized from .313 down to .310. Ask Borjn what happens to the XCB when it resized, please, he's done it.

Send it back to Al, he replaced a undersize 311299 for me w/o problem and was happy to do it.

Tim, is there some requirement that I supply molds to people to test? If so, the reverse should apply and please send me one of your rifles that I might test my bullet in your's or Larry's or Borjn's rifle. I didn't see Larry offering me his rifle to test my bullet. I will offer him the same, pay the return shipping and I won't hurt his rifle. Fair enough?

Now, my bullet was never designed to shoot at velocitys over "Match Velocitys" (approx 2000 - 2200) but, to test it out of spec at ANY velocity is absurd. If you want to test the .313 in a 303 Brit, at normal velocitys, I would would be interested in those results if, done with a open mind.

Frank

Dude! relax! This was just one test.
I was simply stating that Larry followed your instructions to a T. I mean no disrespect by that, it's written a few pages back for everyone to read (post #641). I know what you're saying about not being willing to supply bullets to every Tom Dick and Harry that asks for them, but you're not talking to Tom Dick and Harry. You are talking to the XCB research team. We test bullets, rifles and equipment in a totally scientific, non-biased way. We have done so many experiments that anybody knows that we take things to their limit and test to failure. Any one of us can shoot sub MOA groups, but most of the targets that are posted are larger than that because we stay on the ragged edge.

This thread was started specifically about testing the 30XCB. That is the theme, and our strict methods are well documented.
The ELCO bullet was injected into this thread and people were wondering if your bullet would be a contender for HV or extreme accuracy, so we are testing it. Larry asked for samples from you, and you refused saying to just get a mold from NOE and that "Al has some of the fastest shipping times". That was exactly what was done (and his shipping times are indeed very fast). You are now claiming that following your instructions was a bad idea, so I will put the question to you again:
Would you mind sending me some of your bullets for testing? I will forward them to the team and shoot them myself. Then there would be no question?

I really don't have an axe to grind here. This thread is about learning the truth about what works and what doesn't. All the XCB threads are focused on that, and since we threw all our preconceived ideas and biases out the window, we're actually getting somewhere. Anybody is free to participate, but understand that things will come to the surface, and it's not all going to be good. I was scared to death that my 30XCB design would fall flat on its face, and I feel very fortunate that it passed muster.

But like I said, lets wait and see what Bjorn gets. He also took your advice and spent the money to get his own ELCO bullet mold from NOE. His results may be different.

[frnkeore]

Tim,
No disrespect intend but, why not do a proper test with your bullet. Beagle it up to .313 - 314 .314 would be the right size for your bullet as it's made to cast larger than mine. Then resize it to .310 and shoot it. That would be a fair test. Apple and apple, not apple and orange or other things.

As you state, this thread is about the XCB NOT, my bullet. I can only guess as to why Larry would want to do such a test and add it here.

BTW, Larry states that he borrowed the bullet mold. I can only guess that it was from Borjn at his visit to Larry. If it is Borjn's mold, the mold is just not my design, it must be the OS version and I can't see how it can be used to test anything but, OS bullets in 30 cal.



Frank

[MBTcustom]

Tim,
No disrespect intend but, why not do a proper test with your bullet. Beagle it up to .313 - 314 .314 would be the right size for your bullet as it's made to cast larger than mine. Then resize it to .310 and shoot it. That would be a fair test. Apple and apple, not apple and orange or other things.

As you state, this thread is about the XCB NOT, my bullet. I can only guess as to why Larry would want to do such a test and add it here.

BTW, Larry states that he borrowed the bullet mold. I can only guess that it was from Borjn at his visit to Larry. If it is Borjn's mold, the mold is just not my design, it must be the OS version and I can't see how it can be used to test anything but, OS bullets in 30 cal.



Frank

Honestly, I don't think that they are using the same mold.
The ELCO bullet looked like a good candidate for a HV test by Detox a few pages back, and then the discussion turned to the differances between our two bullets, and then a test was proposed. That's all I know about it. Seems like it all started back on page 32ish.
I still think it was a good idea, and I honestly thought it would do better.

[Larry Gibson]

I thought I gave an excellent example in my previous post of how much accuracy is affected by sizing a .313 as cast bullet down as compared to one that casts at .311? Did I miss something when I gave the example of the 2 different 311466 moulds?

Larry Gibson

[frnkeore]

Testing the NOE309-169-FN at HV

Earlierin this thread I stated;“I conjecture (the 309-169-FN) ELCO bullet may indeed dowell to perhaps 2500+ fps in a 14" twist XCB but doubt it will performwell above that, especially in the 2600 - 2900+ fps range. But then, onlytesting will really give the answer.” Iwas then thinking of Bjorn conducting the test since he was getting or had themould. I also offered to conduct a testof this particular bullet and a forum member was gracious enough to send me his4 cavity mould so I could cast some of these bullets and test them. Thus I conducted the following test:

Since the design of this NOE 309-169-FN isthought by some to be adequate for use at HV I confined my testing to rightaround 2500 fps upwards of 2800+ fps. I decided to test the NOE 309-169-FNagainst the designed for HV shooting NOE 310-165-FN (XCB) and the Lyman 311466Loverin design which is also reputed and proven to be an excellent performer atHV. Thus with the 3 bullets to comparein this test I had 4 cavity moulds for all of them. The bullets were all cast on the same day ofthe same alloy of linotype. A LymanMag-20 bottom poor was used and the alloy temp was maintained at 715 – 730 degrees. The alloy was melted, fluxed with beeswax and“cooked” at that temperature for 30 minutes when it was again fluxed beforecasting began. The moulds werepre-heated and 4 casting done with each before any bullets were kept. The sprue was cut as soon as it hardened andthe bullets were WQ’d immediately. TheBHN ran 26 – 27 after 72 hours.

After aging for 72+ hours the bullets wereinspected for any visible defect. Any visible defect was cause forrejection. The rejection rate was verysmall and was about equal with each bullet. The bullets were then weight sorted with a lot selected for each bullet at+/- .2 gr. The 311466 weighed 150.2 gr,the 30 XCBs weighed 154.1 gr and the ELCO bullets 158.5 gr. The ELCO bullets dropped at .3125 – 313, theXCBs dropped at .311 as did the 311466s.

Hornady GC were used (same box) and initiallyseated and crimped on with the Lyman GC seater on a 450 lubrasizer using a .311H&I die. The bullets were all sizedand lubed (2500+) in the Lyman 450 lubrasizer. Those bullets (30 XCB and ELCO’s) to be used in the 30x60 XCB were thenpush sized through a Lee .310 sizer.

I decided to test all three bullets in the.308W Palma rifle with 14” twist barrel 27.6” long. Researching my records I found 2 loads thatperformed equally well for both the 311466 and the 30 XCB that gave velocitiesof 2500 +/- fps.
A Forster COAX press was used for loadingboth cartridges. All the Winchester test cases (both the .308W and 30x60 XCBare Winchester cases match prepped and fire formed) were NS’d the same using aRedding Bushing die. The necks wereinside uniformed with a Lyman 31 M die for a .002” neck tension. Primers used were WLRs.

The two powders chosen for use with all threebullets in the Palma .308W were AA4350 and H4831SC. A charge of 47.2 gr AA4350 has provenaccurate at 2500+ fps with both the XCB and 311466 bullets as has 48 gr ofH4831SC. Those two loads were chosen totest each bullet with.

Of the several .308W rifles I have thePalma rifle has the longest throat which allowed the ELCO bullet to be seatedwith the top of the GC at the base of the neck. The other two bullets had a bit of the GC up into the case neck also.The bullets were all seated to just bump the leade.

Attachment 140247

Did I misread this?

Frank

[Larry Gibson]

That's what I posted, not sure what you meant it to mean. Another forum member loaned me his NOE 309-169-FN mould. It was not Bjorn btw.

My apologies folks, I took the initial measurement of the ELCO right after casting. Given the obvious discrepancy between what Frank's drop at and what I initially measured mine at I thought I would double check. Measuring 10 inspected and weight sorted bullets gives a measurement of .3118 - .3122. My bad for the confusion.

Larry Gibson

Attachment 140328

[rockrat]

Larry, have you tried a 311467 boolit.? Bit longer/heavier than the 311466. Just wondering. Not trying to get away from the 30XCB people, but while I am waiting on my barrel for my build, just wondering if the 467 might be a candidate for HV along with the 466 and XCB boolits

Thanks

[frnkeore]

I have found it very curious that, in a thread devoted to the 30 XCB bullet I have had to defend my bullet design from such a barrage of negitive wrong and misinformation. Especially when the main people in this thread, keep saying that it is ONLY about the 30 XCB and to not side track it????????????

I never asked anyone to test it and the ONLY one that I said anything to about my bullet was Borjn, after he ordered it, I said that I would like HIM to try it BSed and tell me the difference in the POI between mine and the XCB.

"Measuring 10 inspected and weight sorted bullets gives a measurement of .3118 - .3122."

This only confirms my opinion regarding the mold and casting technics. It either shows that the temp wasn't kept consistant or the blocks had issues closing. What ever it is, the bullets that came out of it were out of spec!!! My design is for a bullet that ONLY needs a GC installed on it and little or NO sizing. I thought that was obvious in my original work up in the NOE thread and my continous reference to that, here in this thread.

As seen in my posted pictures, the mold is made to MY dimensions and I would send any mold back that won't adhere to them. Please do not post results from any 169 ELCO mold that can not drop a bullet .3105 or smaller in lino, as that is NOT my mold!

OT (seems to happen often in this thread) but, this reminds me of my load recommendation for 296 powder in a 8X57. Larry asserted to everyone in the thread, that it could/would cause a SEE and after I said that I would personally test it, he threw caution to the wind and pulled that 98 Mauser right up to his face and pulled the trigger, numerous times with the load that I recommended and proved me right But, he still asserted that it was dangerous!

Larry and I go back a long way with him trying to prove me wrong about a lot of different things. Should I trust what he says regarding anything? With all the wrong assertions that he's made in this thread regarding the bullet I designed ................ any wonder?

Please leave my bullet out of your posts here and if you can't indepentantly certify your testing, please do not test it! That's mine to do. It wasn't designed for what's being talked about in this thread, it was designed for accuracy in ISSA, ASSRA and CBA match shooting.

Please move on.

Frank

[rockrat]

I bought the ELCO boolit to shoot in my Garand and O3A3 at about 2200fps, but was also wondering what it would do at higher velocities. Did cast a few to try in my new barrel once it gets here. Its a linotype/copper alloy and it also casts at .3122" and 159.7gr naked. Will see how it performs.

Back to the 30XCB

[1johnlb]

I have no fight with anyone here and only post to show my findings with the ELCO 309. I have been learning from everyone, and currently trying to get out of the mindset of plinking to shooting with accuracy.

My main purpose has not been pushing the limits but jacket velocities. I have tried to keep my post to a minimum, because in the presents of the others here, I am surely a rookie. And it's been through the generous post of the more experienced that I'm even able to show these groups.

I'm shooting a Savage 10 sa mounted in a choate varmint with a Shilen 30 inch 1in14 and a Vortex sfp.

I'm shooting a copper alloy which is stated on the targets. My babbitt was 18 lbs of range lead with 2 lbs of 50/50 solder and all the copper sulfate that I could get it to absorb. This is my first adventure into this alloy so I have nothing to compare and I hope maybe Popper will add some input. The alloy is 14#ww, 4# monotype and 1# of my babbit. The day I cast, I also sorted, throwing about half back for any flaw. The 2nd day I weight sorted with a .6gr variance and pressed on the gc with a seater, then managed to get half of them sized to 309 and pan lubed with 4 parts 2500 1 part 2700CR. On the 3rd day I started back sizing, the first few were ripping the gc ( gators from NOE )because the alloy being so hard that it wouldn't allow the check to crimp to the boolit. So I had to change over to my 311 sizer which solved my problem. I've not yet shot any sized to 311 but all of them on the targets were sized 309, but I have been having to seat them deeper and deeper everytime I load them Because they seem to be growing.

Unlike the xcb boolit with just the ww and mono mix, the ELCO won't stay on the target after 2600, at 2650 I had them hitting the ground 20 yds in front of the target.







The next pic was the target from the recovered powder from the 6 at 45 gr and the 10 from the 46gr charge of 760 reloaded to 44gr.

I loaded more powders to no avail.

It seems to me thus far I've run out of boolit with the ELCO where I've run out of case with the xcb. I feel that my findings with the ELCO to be in line with Larry's. But given my inexperience and different alloys much more testing is needed, that's probably going to be continued in the 30/06 1in15 that should have already been here if ups hadn't dropped the ball.

Thanks everyone for sharing all your experience
John

[Bjornb]

John,
thanks for posting your results. I was able to do an abbreviated test today; had to leave the range after my rifle developed trigger problems. Bertha has a Canjar set trigger of 1950's vintage, and lately it has showed signs of giving up the ghost. Today I had problems getting the sear to engage, and I finally threw in the towel. The rifle is being shipped to Tim in Arkansas, where she's getting a new Shilen barrel with a 17" twist, and a new Timney trigger. The new barrel will have an XCB chamber reamed all the way to 30-06, so it will be a 30x63 XCB rifle. We are doing this to experiment with more speed; to try to determine just how fast a lead bullet can be pushed with a semblance of accuracy.

However, the trigger issue did not affect accuracy: I fiddled with the bolt and trigger until I got engagement, then the rifle shot normally.

I had cast up a number of ELCO 169 bullets from Linotype about 2 weeks ago. My mould is a 2pb/2gc, and as-cast measurements were as follows:

Fully dressed, with Hornady gas checks and Lars 2700+ lube, the bullets typically weighed:

Bullets were weight sorted to within 0.1 grain.

I decided NOT to shoot the ELCO bullet "against" the XCB or any other bullet; I have shot so many groups with the XCB bullet that I found it redundant. If anybody wants to look them up for reference they are readily available in this and other threads.

I decided to load the ELCO over known charges that have proven accurate in this rifle on numerous occasions. The bullet weighs only a few more grains than the XCB so I used 4 charges that I have shot over and over again with MOA results or better: 50 and 51 grains WC867, 43 grains H414 and 51 grains H4831SC. My shooting protocol was as follows: 5 foulers with same lube and powder as the 10-shot string, shot from a clean barrel (1 wet patch Ed's Red/2 dry patches). Foulers were shot into the berm; I didn't want to be prejudiced by the foulers' performance.

I'll just post target pictures:


I saw no point in continuing after the last group (don't mind the 2 groups recorded by my chronograph; I stopped the group at 5 shots by mistake and re-started it). The bullet clearly lacks accuracy when shot in my rifle; since I'm not a "bullet designer" I'm not speculating about the cause. The bullet also shows poor accuracy as tested at high velocity by Larry and John and while the argument can be made that their bullets were cast or sized to the "wrong" specs, this cannot be said about my bullets. They were cast from an RCBS Pro-Melt with an MBT PID at 745 degrees, and the as-cast dimensions seem to fall within the acceptable parameters.

I had also loaded a number of plain base bullets, lubed with Felix lube, over 10 grains Unique, to see how the bullet would shoot at low speed. With the rifle's trigger function being an issue I found it more important to get the HV shooting done; I'm looking forward to shooting the PBs at some time in the future.

Frank,
once your design has been picked up by a commercial mould maker for sale to the general public, you no longer "own" anything besides your personal copy of the mould. Other shooters are free to test it, we don't need to "independently certify our testing" and our shooting of the bullet will stand or fall on their own merits.

I have read and re-read the posts that were made since Detox first brought up your design (post # 627), and I find nothing said by Larry Gibson that hasn't been born out by testing. As a matter of fact, was I ever to design a bullet, I wouldn't dream about trotting it out to market without letting Larry give it a thorough test.

Maybe you should have done the same.

[detox]

Today I experimented with taper bumping to match bullets throat angle to throat. I reamed a new 30 cal blank PTG die using the same reamer I cut throat with (.310 x 3/4 degree per side angle) same reamer I cut throat with. Now I have to make some matching nose punches to remove pointed bullets from die. Flat nose bullets such as my Accurate 31-200g are very simple to remove without distorting nose. Taper bumping also allows you to check bullet fit for your rifles leade (I like a snug slip fit). I can taper bump the 30XCB or the ELCO bullet very easily. Soft Birdshot is easiest to form and allows heat treating afterwards (size and seat gas check before heat treaing). Linotype alloy is easier to taper bump than I thought it would be.

BTW...Frank knows his stuff!

[popper]

1johnlb Probably too much Cu. You have close to hardball with the Cu replacing Sn. Try 1# of your babbit, below 1% Cu.

[250kt]

Some testing I did today with the XCB. .308 at 100 yards.

[frnkeore]

Since the subject of PB testing of my bullet was brought up by Borjn, I had my first session with it yesterday in my new 30/30 Wesson rifle (1880's chambering done by Frank Wesson). It's a straight taper, 357 Max case necked to 30 cal. finished length of 1.635 and 1.82 CC (28.1 gr water) case capacity.

This group is shot at 200 yards with 85+ deg, heavy mirage and up to 10 mph switchy winds.

2 5/8" group, 8 in 1 5/8". the dot is 3/4 and was dancing 1 1/2" in the mirage. Shot breech seated.
Rem 7 1/2 primer, 170.5 gr bullet, in 22/1 alloy

11.5 gr Ramshot Enforcer (same as AA4100)
1611 FPS ave
12.7 SD
44.7 ES

Frank