I want to build a 30BR for Cast Bullet Shooting. Was thinking of going to a 0.333 neck to give me room for a .310 bullet. I currently am shooting an NOE Clone of the Lyman 311299 in 308 Win with good results. Any suggestions for neck diameter and throating from you guys who have already done it?
Thanks
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You can get great results by throating your 308. I used a .310 diameter by .75 degree per side taper reamer. Use the same reamer to make die to taper bump bullets to fit throat. Bullets with long bearing surface work good (LBT style comes to mind). Reloader 7 powder works good.
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I'd call Dave Kiff at Pacific Tool and Gage and have a conversation with him. He'd have an opinion on the neck cut and if you send him a couple dummy rounds he'll probably be able to work up a drawing for you to look at. But I would recommend designing the throat to something other than the 311299 look alike.
As long as the bullet nose fits the barrel bore Bore Rider designs are super friendly to load and they don't give you the bullet to lands interference a ball seat or tapered design would when you start to look to have the gas check sitting in the bottom of the neck rather than in the shoulder. Full disclaimer; rigs can shoot very well even with the bullet below the neck but since you're starting out with a new barrel, reamer you might as well get the throat right and still keep the bullet in the case neck.
And it would be nice if the bullet you send them will kinda fit the norm for a custom barrel, assuming a .3000 bore. I have a 31-220G taper design that drops at about .3002 at the nose and about .3062 in front of the driving band. If you need a few to work with let me know. Everything else I have is oversized to fit the oversized bore I'm working with.
The results from the CBA Nationals will give an idea what others are using. There's a couple Spitizer with most others either Egan design or the straight taper from Accurate.
I'd be careful about running a tight neck. Jacketed br shooters run .0005 per side but they don't hand size alloy cast bullets that have a gas check pressed on the base.
I'd be great if others would chip in regards to throating and tight necks.
A “Measured Response” is as effective as tongue lashing a stuck door.
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Keep in mind the .30BR has no standard. Consider the lifespan of the barrel and how much you're willing to spend and spend again. As you get throat erosion what will do to mitigate it. If you start on the tighter throat there is room to go to a larger nose profile in the future. What cartridge are you going to use as your base and reform to .30BR? What steps are you willing to take to make the brass fit. I just measured a sample of my .30BR brass and some of what I have would not fit in a chamber with a .333 neck and a .310 bullet. I have neck thickness between .010 and .014. My old brass which is Norma is the thicker end. I do not have any idea what if anything my Dad did to fit it to the chamber. My new and newer brass is Lapua and was just necked out to .308 and fire-formed. I don't have dies. I de-prime with a tong tool, reprime with a lee hand primer, charge with a Lyman measure and hand seat the bullets to the depth of the gas check. Custom dies are available if you need to go that route. If you are paying someone to chamber your barrel have them cut a form die with the same reamer(s). I have one. I have reformed .30-06 Lake City brass in one press stroke with just sizing lube, just to see if I could. Trimming to length would have been more work than I was willing to do. It was more of an experiment.
If you are going the custom reamer route pick a bullet first. Hopefully one that drops nicely and is uniform from a single cavity mold. If that is the .311299 clone so be it. Send a few samples to the reamer maker to match the throat, along with your intended OAL.
https://www.jgsprecision.com/ offers such a service.
Your proposed neck dimension of .333 makes sense to me if you make sure your necks are no thicker than .010, that should give you with .0005" clearance each side with a .310 bullet. However this is just based on my understanding of what I have read. I don't have any real world knowledge. In reading match results I have noticed that most heavy rifle shooters do not list or do not have any throating and they also either do not list or do not bump their bullets.
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A little insight into two lines of the data chart supplied by Wm Cook: - HVY Class Hart 24" 1-13" twist barrel is a .331" neck 30br - UNR Class Lederer 28" 1-13" twist is also a .331" neck.
Both rifles belong to my father. There are multiple 30BR's in his possession, and all of them are .331" necks. They all shoot very well. He does all of his neck turning based off of a .312 bullet diameter, with the ability to run a .310 in the same case just a little dirtier.
You will find that most 30BR's will prefer a borerider or custom bumped/tapered bullet to match the throat. We have a few bullets that will shoot straight out of the mold, but they're odd to find.
Jeffrey Sechrist Co-Webmaster
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Here is one from PTG's book of chamber prints. This one has a 1 degree throat angle. I do not know if that is included or per side angle.
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There’s a bunch of good information in the above post. Not in any particular order:
Jeffery:
A plug for the Egan design. It’s a bore rider but in front of the front driving band you have .010 to .030 thousands that tapers from say .3070 to .3000 that’ll give you greater bearing surface. It’s a bore rider by design but what sits in the freebore before the leade is > than .3000 so it is a true bearing surface. And with a custom mold you could run that chubby portion out further. Custom mold makers are very accommodating and in my opinion, dollar for dollar it’s the most important money you'll spend.
Good luck, Bill.
A “Measured Response” is as effective as tongue lashing a stuck door.
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Hey Jeffery, one last question. What does "none" mean where it shows the throating on that HVY Class Hart 24" 1-13?
A “Measured Response” is as effective as tongue lashing a stuck door.
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Believe right now we are turning between 9-9.5 thousandths thickness on the neck. -I'm not 100% sure on the free bore. -And we currently use Peterson 7br brass but we also use the 6BR brass if the seven is not available. -That rifle has the barrel on it that it came to us with and we are not 100% sure what the throating actually is.
I will follow up by saying that some of the barrels are 0.300 and some are 0.301. Both will work.
Jeffrey Sechrist Co-Webmaster
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Further note on that rifle, that is a panda action rifle that was originally owned by Mr Tom Gray.
Jeffrey Sechrist Co-Webmaster
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Hart barrel, Panda action shooting cast! That’s a really nice thought to start Christmas Eve with. Thanks for sharing and Merry Christmas. Bill
A “Measured Response” is as effective as tongue lashing a stuck door.
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wimilkman
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Tom Acheson
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Aaron
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BRatigan
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Ed Harris
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mashburn
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