Cast bullet "nose riding", for precsion shooting

dthunter

dthunter

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I have been thinking about that "nose riding" thing.

Getting a cast bullets nose to snugly align itself into the rifling before the rifling fully engauges the bearing bands.
Do any of you gunnutz have any experience with this?
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First, I tried seating my bullets further and further out of the case neck, and into the rifling.
I was hoping that I could seat the bullet far enough forward to get the gas check to start into the case neck.
To protect the base and bullet bearing surfaces from the firing sequence gasses.

Seating my bullets about* 0.150" further than I had before, I noticed that as I locked the bolt closed, I could feel the bullet slide/engrave into the rifling.
I lifted the bolt, and had to pound very firmly back on the bolt to open the action, and remove the cartridge/bullet.
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This time the front major bullet bearing band had a clearly defined rifling grooves, AND the bullets nose had clear indication of tapered rifling marks. Is this what we are looking for?
By the way, the noses on my bullets vary between 0.301 & 0.03027" in diameter.
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I have seated bullets into the rifling before when using jacketed bullets,* and that always made me feel a little nervous about spiking pressure potential.
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Is this much bullet engraving with the cast bullets "normal" for Cast Bullet precision shooting?
If so, I will go after it, and continue to experiment, and load develop.
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At this point, the gas check is probably just entering the bottom of the neck. I suspect that* the combustion gases will still get to the side of the bullet base, before, the neck completly encompases the bullets base. But MUCH better than before.
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Do you experienced cast bullet*target shooters have your rifling lead machined to allow for this style of shooting, or a custom mould made?
Let me know what you think.
 
I don't think you will have a problem... One thing you should maybe check out is measure your overall length before and after you chamber a round just to ensure that you are not pushing the bullet back into the case... If this is happening it may not be happening uniformly and your accuracy results could be less than desireable...

A little more info may also help out... what caliber, bullet weight, powder charge...etc...
 
Thankyou for the response

ckid said:
I don't think you will have a problem... One thing you should maybe check out is measure your overall length before and after you chamber a round just to ensure that you are not pushing the bullet back into the case... If this is happening it may not be happening uniformly and your accuracy results could be less than desireable...

A little more info may also help out... what caliber, bullet weight, powder charge...etc...
Click to expand...

This is for a remington 700, Varmint Laminate, .308Winchester.
Lymans 170 gr. #311291 gas checked bullet. ( actual weight=177gr.)

I am starting with a brand new rifle, and want to start with all the advanced methods to shorten the search for a decent load.
I unserstand that it will take some experimenting to refine it.

Good point about the potential change in OAL creating pressure variations.
I will check it.

Do you crimp your cast?, or will the deep seating depth accomplish the same thing?
 
As to your question on crimping.... It all depends what rifle I am loading for.... If it for any magazine fed gun, I crimp.... For my single shots or magazine fed guns that I single load, I use the crimp die to just remove an evidence of the flare at the case mouth...

Your seating method should provide enough resistance that a crimp is not essential... However if you are using the magazine you may want to apply a crimp...

Years ago I tried some cast gas checked bullets in my M70 .280 rem and with the bullet design I was using even when seated to heavy bullet to land contact as signifcant portion of the bullet was below the case shoulder.... I could not get this bullet to shoot worth a damn and eventually gave up on the idea...
 
You shouldn't have to crimp bullets in a bolt action rifle. That said, if you're going to continue seating them that far forward, you may have to crimp to avoid sticking them in the rifling. I don't think it's necessary to seat that far forward, you should only be TOUCHING either the bullet nose or driving band, whichever is first. The gas pressure should bear on all sides of the bullet base equally, thus not damage it.
If your mold - which is usually a good one - won't fit your chamber,you may have to find a design more compatible with .308. As well, you could try a softer alloy like 20:1 lead and tin, which would engrave easier and might cast a tiny bit smaller.
Grouch
 
That is a good bullet to start with, lots of options, the dia. of bore riding portion can not be increased except by using a harder alloy. To decrease dia. of bore riding portion, I size bullet with .301" or .300" or .302" by sizing nose first on Lyman or RCBS sizer and flat top punch. The bullet will not go in further as you will hit first driving band, next size and lube the normal way with(in my case).310" sizer....Ben
Note: I don't believe this (partial sizing) can be done on Lee or Star equipment.
 
No resistance,even with hardcast, but you need to know what size you need for that front portion before you spend lots of money on diff. sized bullet sizing dies. You can actually tell pretty close by inserting bore riding portion into the muzzle end of barrel, fit should be tight but bullet prolly should not engrave......Ben
 
If you have rifle with short throat can I suggest C312-155-2R?

Size it to .311 and give it a shot.I'm using it in Israeli K98 due to above mentioned reason.It is also in 308 Win.

There is an active group buy going on right now on Cast Boolits for this mould from NOE-it will be made to much better quality that Lee.
 
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