lands engraving bullet?

[Texxut]

I'm new to cast bullets in rifles.
I'm trying to set up for a loading of 3006, useing a cast bullet (WW), from an RCBS 30-180-SP gas checked mold. (This mold drops a 192 grn bullet) My problem is, when I seat the bullet so the GC is at the base of the neck, not below it, the top band engages the lands of the rifling. It is my understanding the GC should be in the neck. But the bullet should not be engaged in the riflings. Is this safe to have the bullet engaged in the lands? I always thought that was not a good idea.
If the GC can't be below the base of the neck, how are you guys shooting anything heavier than 115 grns with a GC on it?

[Ben]

Who said a g/c can't be below the neck ?

That particular bullet design looks like it is going to force you to deep seat it , in order to close the bolt. You might want to try an alternate design.

[lonewelder]

Light engraving is ok,so long as the action is not hard to close.

[Texxut]

Ben,
Unless I misunderstood what they mean, ( I'm new to cast bullets in rifles.) Lyman reloading handbook ed 49, Pg 84;

"CAUTION: old style press-on gas checks should not be used when bullet bases go below the neck. This will avoid having a loose gas check fall into the powder charge. Accuracy, with any style cast bullet, will always be best if bullet bases are completely contained within the neck of the case."

I'm using Hornady GC applied with an RCBS LAMII lubersizer. Are these what they are talking about. Or am I good to go by deep seating these GC'ed bullets?.

[Ben]

I've read that before also. There could be some truth to that if you were using the old style Lyman g/c's that were not of the modern " crimp on " design. If you are using Gator checks or Hornady crimp on g/cs & you can't pull them off with your finger nails, you have nothing to worry about.

Seat them and shoot them.

Ben

[Texxut]

Thanks Ben.
I'll seat them just enough to clear the lands.
Now I can get started.
:drinks:

[lonewelder]

Hornady gas checks crimp on.I think that reffers to the older style that do not.That boolit looks like it will be awfull deep in the case.I think Bens advice of another style is best.

[Larry Gibson]

In many instances GCs below the case neck can cause inaccuracy. This has been known for some time and there is an article in the latest Handloader confirming it. However, it is not always the case and whether inaccuracy results is dependant on Alloy, lube, burning rate of powder, intensity of load, etc. Sometimes you get away with it.

In my limited experience over 40 years or so of shooting cast bullets I found I do not "get away with it" more often than not. Thus it is my procedure to keep the GC in the neck. However, this does not mean the GC has to be entirely in the neck as shown in your picture. I have found the as long as the top of the GC is inside the neck very good accuracy is possible/probable. Thus you can seat that bullet a bit more and still have the GC "in " the neck. Also it is also manytimes helpful to accuracy if the driving band is slightly engraved by the leade/rifling.

Larry Gibson

[Texxut]

Lonewelder,
I'll roll up dummies, backing it off till I'm no longer against the lands, and see what that gives me.
If the COL is within data listed in my books, I'll try it.

[Texxut]

Thanks for the info Larry.

[stubshaft]

Looks like a 311644 Lyman bore rider not a 30-180-SP. The Lyman has those grooves for additional lube. I used both of them in my Wichita 30BC. I have a couple of moulds from the RCBS custom shop (usually marked with an asterisk), but have never seen an RCBS like that before.

In any case if you wanted to seat it out you could have Buckshot make a nose sizing die and size up to the bottom of the second nose lube groove.

[excess650]

I seat 'em out so that the front driving band at least kisses the rifling. Light engraving on the front band doesn't hurt, provided that you can chamber/unload without leaving a boolit stuck in the throat. My 311041 clone engraves most of the nose in my old Savage 30-30 carbine.

NEI made molds with DD bands out on the end of the nose for bore riders. I suspect that was their way of aligning undersized noses, and that narrow band was meant to be engraved.

Most of the new GCs crimp on, so no problem with them below the neck. Older Lyman GCs were a "slip-fit" and could be easily removed. IIRC, the ide was that they would drop off in flight. I DO know that some of them did not crimp into place. I have a .357 case with GC firmly seated 1/3 way down, but the boolit was pulled with a kinetic puller.

[Jim]

As has been suggested, seating the boolit so the front band kisses the riflings is not altogether bad. If you seat the bullet so that the front band is rammed into the riflings, that COULD cause chamber pressure to be a bit high. Without a jump start on the riflings, the boolit is experiencing more resistance to get moving than it would if it were only retained by the neck tension. Just be aware of that and watch your pressure signs.
Like others, I have used boolits that MUST be seated deep in order to chamber. I've not seen any signs that indicate this reduces accuracy, but then, I don't shoot at hundreds of yards and I'm not trying to qualify for the Olympics.

[MtGun44]

The big issue is will the engraving potentially move the boolit into the case on chambering
or pull it out if unloaded without firing? The former is unsafe as it can increase pressures, in
some situations very dramatically, and the latter is a huge PITA as you will dump a whole
case of powder into the action while leaving a boolit stuck in the throat.

Bill

[adrians]

i have some lyman ( "brass" g/c's) and hornady (copper),so the lyman are best if in the neck, and the hornady can? be set below the neck?, the lyman ones don't pass the fingernail test the hornady crimp on so they are on for good.
what can happen IF the lyman g/c's fall off in the case before firing?
very curious ,,adrians. :evil::coffee::evil:
have a great weekend.

[oldhickory]

Texxut, I had the same issue with the RCBS 30-180-FN in a .308 M70. I loaded dummys, to what I thought was the max seating depth to keep any portion of the lead boolit itself within the neck and chambered it. The top band was fully engraved in the rifling and the bolt was hard to close. My next step, (I really wanted to use this boolit in this gun) was to take another sized and trimmed .308 cartridge to the bench grinder and grind off about 1/2 the circumfrence of the neck, shoulder, and body about 1/2" back. This gave me a true look of what was what inside the case. I found I could seat the boolit a bit deeper, keeping the lead shank totally protected with a portion of the gas check below the neck a bit. Lo and behold, that tiny bit gave me the clearance I needed in the bore. The front band still does lightly engage the rifling, but it's minor and no boolit set-back occurs.

I was able to seat about .025" deeper still protecting the lead, and that was enough. BTW, I agree with Larry, unless velocitys are kept to plain base boolit levels, I think you're inviting poor accuracy and possible leading by seating them below the gas check-neck line. Just my opinion.

[Texxut]

Thanks Oldhickory, I'll try that and see what that gets me. I don't have a lot of molds, so I'm hoping to make this one work.

[Three44s]

Quote by stubshaft:

"In any case if you wanted to seat it out you could have Buckshot make a nose sizing die and size up to the bottom of the second nose lube groove."


Texxut,

I'd really consider that suggestion. As I look at your picture you have a lot of boolit shank to bury!

I have heard stellar things about Buckshot's abilities and specifically making custom sizing dies for boolits. A nose sizing die from him could well be the ticket to utilize the mold you are working with.

Three 44s

[turbo1889]

Well, I guess I'm just a horse of a different color.

I WANT to get my boolits to engrave in the rifling. The more I can get them to engrave without having problems such the boolit being pushed back in the case, being pulled out of the shell if the cartridge is removed from the action without firing, or aggressively raising peak chamber pressures the better.

In fact I currently have one new-ish mold of my own design that has proven itself very well over the last few months that is specifically designed for the bore-riding section of the nose to engrave in the rifling:

http://farm6.static.flickr.com/5288/5222787752_4087e6a457_z.jpg (http://www.flickr.com/photos/54455625@N04/5222787752/)

http://farm5.static.flickr.com/4088/5222729730_235c78266b_z.jpg (http://www.flickr.com/photos/54455625@N04/5222729730/)

http://farm6.static.flickr.com/5244/5222729156_c8524822d9_z.jpg (http://www.flickr.com/photos/54455625@N04/5222729156/)

As you can plainly see in the CAD diagram and second photo the boolit is a two diameter bore riding design. None of the guns I shoot this boolit design in have a minor bore diameter that are greater then 0.303” and most of them are in the 0.302”-0.301” range which means that at the very least the very front micro TL type band is engraved in the rifling and usually the rest of the bore riding micro TL type bands as well. So far the boolit has shot with better accuracy then I can hold with iron sights in several guns chambered in 303-Brit, 7.62x54R, 7.62x39, and even a 7.7mm-Jap. With one of the 7.62x54R guns that is equipped with a genuine WWII era Soviet sniper scope I have even shot it out to the 300 yard line with plenty enough accuracy to satisfy my personal expectations for a PB cast lead boolit fired from a high pressure bottle neck cartridge at that range.

I intend to continue along these lines of development and have drawn up a heavier second generation design to work for my standard (non-fat) 30-caliber rifles (30-06, 308, etc . . .):

http://farm6.static.flickr.com/5176/5437753130_c92c83c91d_z.jpg (http://www.flickr.com/photos/54455625@N04/5437753130/)

So, long story short, I think being scared of the boolit engraving in the rifling is a load of felgercarb. Provided it is done correctly, so as to avoid potential problems that have already been outlined it is of considerable benefit to the performance of the load rather then a detriment. Especially if one is using large charges of very slow burning powders to send ones cast rifle boolits for modern bottle neck cartridge down range using the “soft launch” technique of using a long medium pressure burn curve such as I do.

[303Guy]

I WANT to get my boolits to engrave in the rifling.I'm with turbo1889.

Great boolit design, turbo1889. :idea:

Ummm .... would you mind if'n I were to 'borrow' your idea in the future?:roll:

[turbo1889]

Thank you for the compliment, although I'm not entirely sure if I deserve it.

I am merely exploring a new design concept that is not entirely unique by any means. The basic concept was pioneered long before I by the late master craftsman Mr. Walt of NEI in the form of a single raised band on the nose of his bore riding designs. Modern machining processes have allowed more complicated and precise mold cavities to be cut using machinery and techniques that were not available to earlier mold craftsmen that now allow nearly the entire bore riding surface to be covered with precisely formed micro bands.

As to you or anyone else copying the design, at this point only a few such molds so designed are in existence and although initial testing has proven quite favorable it still remains and experimental design concept and I cannot guarantee success so you copy at you own risk of failure.

[leadman]

I typically seat my boolits on purpose to engrave the rifling, except for hunting loads where they may have to be extracted.
I get better accuracy this way.