Plain-base bullet alloys?

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.22-10-45 posted this 3 weeks ago

Helo, l need advice on shooting plain-base bullets in modern smokeless powder rifles.  I have been having  success using a Lyman #2 equivalent alloy of ww &50-50 solder or range lead& steriotype alloy with gas checked bullets.  I have heard plain base must be softer?  I have softer aloys, 20-1, 25-1, and even softer.  I Wil be using in 6mm, .25 & .30 cal.  Powders are H4227 & Vihtavuori N130...can I use these in reduced loadings or do I need faster powders?  Thanks!

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RicinYakima posted this 3 weeks ago

I have no advise until you tell me what calibers and what is the goal. I have shot a lot of 25/20 and 250/3000 plain base and 30/30 and 8.15x for plinking. H4227 is the slowest I ever used and mostly used shotgun powders. FWIW

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Wm Cook posted this 3 weeks ago

This may be useless to help you answer any of the questions you're looking answers for but this is a data pull from last years Nationals.  The fact that it is breech seated and the cartridge choice they use/you use may eliminate this as being any value to you. 

However the velocities this group was shooting and alloy blend used should be of some value. 

I'm hoping that there is a relationship between case capacity, bullet weight and powder but haven't been able to prove that yet.  Curious about the case capacity of the 32 Miller.  So the PB competitors used a lot of AA9 and 4100.  And those powders are a few steps faster then your 4227 and N130 you mentioned.  That said I've shot a bunch of low velocity plinking loads with Red Dot, Bullseye and Unique.  If PB needs lower velocity to seal the powder burn it doesn't take much of any of the pistol powders to get it in the >1200fps / <1450fps range

If we were discussing this in person the first thing I'd ask would be what cartridge you'd be using, what velocity you were going after and your accuracy expectations. Keeping 1400 fps in mind and alloys in the 25 to 1 range seems like a practical place to start.  Good luck, Bill C.

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Eutectic posted this 3 weeks ago

The breach seat data is great if you breach seat. I would guess you are loading a conventional fixed cartridge. You want 1000 to 1200 fps and any of the fast pistol/shotgun powders mentioned will give the best results. I shoot 6 grains of Red Dot behind 150 -170 grain plain base bullets in my 30-30. Alloy is not critical,  big_grin

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.22-10-45 posted this 3 weeks ago

Sorry, I should have given calibers.  6mm is the old .236 (6mm)  Winchester-Lee Navy straight-pull sporting rifle., a .25 Ackley krag in a Sharps Borchardt action, and the .30-40 krag in an Al Story Borchardt.  I am only after accuracy, I have Ben using 10gr. H4227 & 10GR. Trail Boss in the 6mm with Ideal 245498 g.c. 18gr. H4227 In the 6mm,  18gr. In Ackley krag with 100gr. Bullets & 14.5 to 18.5gr. H4227 in the krag with bullets between 170gr & 200gr. g.c.

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gnoahhh posted this 3 weeks ago

Were it me I would start with both 1:20 and 1 : 30 tin/lead alloys. The rifles will tell you which they prefer. I shoot a lot of PB bullets, breech seated and fixed, in stuff like .32-40 and .25-20 Single Shot and invariably I find Nirvana with one of those two alloys. I've also quite recently started playing with a custom Martini Cadet with a 26" barrel chambered in .357 Maximum, and with loads in the 1700+ fps range with a 200 grain bullet I found 1:20 alloy to give excellent accuracy and no leading - albeit with a gas check.

 

I think also if I were to skate on the edge with PB loads, say over 14-1500fps, I would use a grease wad under the bullet. I started using a dental wax wad under my breech seated .32-40's and found a measurable increase in accuracy, no leading but a bit of extra "waxxy buildup" that necessitates a bit of extra effort when cleaning after a day involving a couple hundred shots (with one cartridge case). (Counterintuitively accuracy remains superb to the end despite the build up.) After hunting season and before the spring match season I'll be mixing some old time grease wad formulas, pouring into sheets, and employing like I do with the dental wax by pressing the upright (and charged) case mouth into it cooky cutter-style. I know it's been done to death in the past, and results may all be in my head, but I see merit in it and am determined to re-invent the wheel come hell or high water!

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Wm Cook posted this 2 weeks ago

.22-10-45, first off I have to offer my appreciation for your hardware. Starting out with a couple of Borchardt’s to take on shooting accuracy with PBB would be an enviable position to start from. IMHO I believe that the accuracy you achieve will only limited by the effort you want to put into it.

After conferring with my mentor I would suggest going directly to breech seating.

One of the first “to do’s” would be to find a mold that drops a bullet that would fit your throat, bore. I have no clue what the options are out there for the .25 Ackley krag or the .30-40 krag. But I’m certain there are people on the forum that could fill in some of the blanks.

With 20-1, 30-1 alloy, your first guess at what mold to start with, target velocity around 1400 - 1450 fps, pick a powder (I’d be pressed not to try 4100, AA9) and I’d give it a go.

I’m as naïve as they come but this looks like fun.

Option two would be what others suggested and shoot pistol powders and plink at 25 to 50 yards. No harm in doing that.

But dang those breech seaters shoot some eye popping groups at 100/200 yards. Good luck, Bill.

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Ken Campbell Iowa posted this 2 weeks ago

no one in this thread has mentioned powder coating with plain base ... 

be interesting if someone tried PC in an accurate rifle with significantly different alloys and otherwise plain base ...

***************

hmmm . wonder if i could get that last 100-200 fps in a 45-70 with PC on a 405 gr cast plain base ? ...  ( 2 moa being the cutoff ) 

ken

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lotech posted this 2 weeks ago

Someone mentioned grease wads. I think very few use them today and have little or no knowledge of them. It's been so long since I used them in both (straightwall) rifle and pistol cartridges, I can't remember much, other than I did have limited success as for as accuracy and freedom from leading. In some instances, however, accuracy deteriorated. 

I bought a Cabine Tree grease wad extruder years ago with great hope for it. It's mostly gathered dust. 

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Green Frog posted this 2 weeks ago

When I first got interested in single shot rifles I read the Roberts and Waters book on the subject and got the suggestion to use 25:1 pure lead to pure tin.  I shot this combo then and now for 32-40, 45-70 and whatever else came along in (smokeless) schuetzen.  My favorite powders then and now are IMR 4759, IMR 4227, H-108 and of course Alliant 2400.  I also use it with black powder for 50 Maynard percussion, 45-70 BPCS, etc.  I won't say this is the best alloy for everyone, but in the words of Rick Hunter, "Works for me!" cool

Froggie

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.22-10-45 posted this 2 weeks ago

I purchased an Ideal 308403 mold..this is a H.M. Pope design.  Last weekend I was able to try it out.  Using a 20-1 lead-tin alloy, bullets have the following dimensions: base band dia. .315".  The following 6 bands measure:  .3045",  .302",  .3005,  .3005",  .3005",  .300".   The Lilja barrels throat measures .310", and I cannot insert base of bullet into a fired case as this bullet was designed to be loaded.  I Wil have to run them thru a .312 sizer to fit.  Or I could try breech- seating.

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45 2.1 posted this 2 weeks ago

Pope designed that bullet to be lubed and hand inserted into a fired case neck for match shooting. The drawing in the CBA blog: https://castbulletassoc.org/blog/article/2017/11/124/the-lyman-pope-308403 was drawn by me from several as cast samples. The bullet has a tapered base band that is smaller at the base than the top of that band. It should have entered a fired case neck in most rifles unless the case mouth was deformed out of round. The bullet was meant to be cast very soft out of a lead/tin alloy.

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Tom Acheson posted this 2 weeks ago

Can’t add a lot to this, but…

My Plain Base Bullet CBA match category rifle is an old Remington Rolling Block, chambered in .38-55. For two match seasons I used fixed ammunition, with mixed accuracy results. A few “local coaches” told me that the best accuracy would be achieved with breech seating. However, they insist that my 20:1 bullets are too hard. They also said even 25:1 is too hard of an alloy, for breech seating. The bullet needs to be soft enough so that it can be “coaxed” into the rifling with the seater tool. Along with this, there is a need to be sure your bullet is the correct OD to have breech seating be effective.

One of my coaches is making me a breech seater. Once I have that, I’ll try 30:1 alloy.

FWIW

Tom

 

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45 2.1 posted this 2 weeks ago

If you try an even softer alloy... such as 50:1 in fixed ammunition you can achieve comparable results to breech seating. I've used the Browning Traditional Hunter in 38-55 and 45-70 in this. Powder was SR 4759 in both calibers. You need to get a really soft bullet that bumps correctly for the powder charge to do this.

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Wm Cook posted this 2 weeks ago

I’m finding this thread fascinating.

There’s such an incredible range of practices being used to chase cast accuracy. Unrestricted is shooting Linotype, hardness ~22 and velocities of >2000fps while PBB are shooting 20:1 - 30:1 with a hardness of ~9 @ 1400fps.  

Don't go apoplectic on me.  I know the two classes are apples and oranges and they can not be directly compared.  But darn it they're both shooting aggs <1" in registered competition.

Just a quick note on breech seating.  I'm clueless about the "how to do it" aspects of breech seating but I found this thread that filled in a few gaps for me.  Thanks again for stretching my knowledge base.  I appreciate it.  Bill C.

 

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.22-10-45 posted this 2 weeks ago

45 2.1 is spot on about the 308403 tapered base intended to fit a fired case.  However, I think Ideal was hedging their bet on this bullet fitting various .30 caliber fired cases, especially those cases fired in generously sized military rifles...at least for the Ideal mold I have.  Measured bullet base of 20-1 lead-tin alloy with Starred .0001" micrometer and I get .3150".  The fired cases from the Borchardt .30-40 are a very close slip fit for a Brown & Sharpe .310" plug gage.  So close that if pin is started in case mouth, and case set upright,  the pin slowly decends into case supported by air column.  It comes out with a pop.  A .311 pin will not enter.  This is probably one of the reasons this rifle shoots cast so well.

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Tom Acheson posted this 2 weeks ago

It is interesting that the two CBA gun categories are so far apart but so close…..no restriction on either gun—-barrel length, weight, modifications—-and the rests….anything goes. Just need to use plain based bullets in the one. The match rules don’t even exclude bolt actions for use in the Plain Base category.

Tom

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Wm Cook posted this 2 weeks ago

My friend told me about someone over there that competed with a bolt action .223 breech seated.

Maybe the brass is springing back that far? I’d be tempted to pound cast to find the actual chamber neck. If you reverse pound cast from the chamber end what’s the freebore cut to?

If it is brass spring back and your freebore can take .315, maybe you could expand the case neck instead of sizing down the bullet.

At least you got feed back on your question in the OP on alloy. The consensus seems to be no harder than 20:1 (10) a semi sweet spot of 25:1 (8) to uncharted territory of even softer alloy.

Once the bullet fit to case/freebore is resolved the next to do is working on what velocities/powders you’ll use. Fun project, Bill.

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RicinYakima posted this 2 weeks ago

Rules do exclude bolt action guns in plain base. 

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Tom Acheson posted this 2 weeks ago

Unless I’m looking at an outdated rule, here is the May 21 rule….


Rule 5.5.  Plain Base Bullet Class - Any rifle meeting the requirements of 5.4 (Unrestricted Rifle) may be  used in the Plain Base Bullet (no metallic gas checks) Class. The Plain Base Bullet Class  does not prevent the use of plain base bullets in other classes. Breech seating is allowed.

It does not exclude bolt actions.

As in some of the CBA rules….if it doesn’t say you can’t do it…..you can do it.

Tom

 

 

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Tom Acheson posted this 2 weeks ago

Comments about the CBA match equipment rules aren’t really helpful to the OP. 

I have a Model 74 Sharps, a black powder cartridge rifle (BPCR), that I’ll be casting for when the outdoor temperatures allow me to stand in the garage for a few hours. I only use black powder. The bullet this time will be a Brooks paper patch type. I frequent the Shiloh Rifle forum. It is surprising how many posters discuss the use of an alloy of 30:1. So my next bullets will be the softer 30:1 composition. Previous to this, I was using 15:1, 16:1 and 20:1 alloys.

Tom

 

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