PDA

View Full Version : Nose shape and Accuuracy



Wayne S
04-11-2012, 01:16 PM
strictly from an accuracy potential stand point, and everything else being the same;
weight, size & fit to the chamber/throat, length and % of bearing surface to OAL which would shoot smaller groups at 100 & 200 yds. A FN or a RN design.??
The best example in design would be Lyman's 31141 and their 311291

rhbrink
04-11-2012, 01:19 PM
Semi spitzer more like the 311299.

MtGun44
04-11-2012, 03:34 PM
Wrong end. Accy comes from the back end, not the front.

Bill

44man
04-11-2012, 03:59 PM
Only in the revolver is it important so the nose itself aligns the cylinder.

462
04-11-2012, 03:59 PM
Handloader (?) did a test in which the noses and bases of numerous bullets (jacketed) were purposely damaged, in a number of different ways, then they were all identically loaded. The bullets with damaged noses all showed the same accuracy. The bullets with damaged bases all showed a substantial loss of accuracy.

Wayne S
04-11-2012, 04:45 PM
So, then there should be no difference in accuracy if both the bullets are sized, and loaded the same and fired in the same weapon ?
Neither nose section touch's the lands.
http://castboolits.gunloads.com/showthread.php?t=118211
and
http://castboolits.gunloads.com/showthread.php?p=1411073#post1411073

runfiverun
04-11-2012, 08:17 PM
not really.
i shoot the rcbs 055-sp.
i also swage it into a 6s nose with a bigger meplat.
and hollowpoint it too.
they all give about the same accuracy.
just i can get it at a little higher velocity from the bumped nose.
which actually has a short bore riding section.
an unsupported nose can slump and a longer one is more susceptable.

Wayne S
04-11-2012, 10:50 PM
not really.
i shoot the rcbs 055-sp.
i also swage it into a 6s nose with a bigger meplat.
and hollowpoint it too.
they all give about the same accuracy.
just i can get it at a little higher velocity from the bumped nose.
which actually has a short bore riding section.
an unsupported nose can slump and a longer one is more susceptable.

Thanks,
This question came up while I'm trying to decide which of the two above listed molds to send off and have D.D. rings cut into their noses, since my Contenders have the usual T/C long throats and the 55-MX-3 Mold won't be out till way later this year.
Thanks all for your help

Frank
04-12-2012, 12:40 PM
Nose affects form stability. A spitzer flies better than an FN. But an FN is better for hunting. Either bullet loses out because it's a bore rider. With a long throat why don't you fill it up with driving band? Handloader is wrong because when you soft point a bullet you have to be careful not to distort it seating. If you affect the nose, the accuracy will be effected. :brokenima

popper
04-12-2012, 03:58 PM
Both ends will effect accuracy. The base determines flight at launch and it can't get any better(unless it has propellant and controls). Gyro and aerodynamics take over then. Gyro effects are determined by changes in fps, rifling and bullet imbalances. Aero effects come from bullet shape and fps. Flat points slow down faster but put more mass in front(think of an arrow with the weight in back - will swap ends). Spire point doesn't lose fps as fast(longer range) and HP(properly done - for Frank) generate a curious pressure front and can be more accurate at shorter ranges. In generalities I would say sharper point for long range HV and blunt point for short range LV. Bullet sales pretty much agree with me (how's that for an ego?).

Wayne S
04-12-2012, 09:37 PM
the nose section on both molds [listed above] drop into the front driving band when placed in the bore at the muzzle.
The only way I can get any assurance ** that the bullet will be centered in the throat is to seat both bullets long, actually exposing 1/2 of the lube grove
The D.D. ring I plan to have cut just past the ojive is a procedure that NEI started, it adds a ring, like a skinny driving band to the nose, this ring should allow me to seat the bullets so when the action is closed the DD ring will be engraved into the rifling.
Since the top punch must go below the surface of the H&I die to get lube in the lube grove, I may get "Buckshot" to make me 225 spire point top punch and try a little nose bumping,
As to accuracy, I'm striving for < 2 MOA out of a 10" T/C 22 Hornet

Frank
04-12-2012, 11:30 PM
Popper:

how's that for an ego?
Sounded good to me. I didn't perceive any ego. Just normal, bullet talk. But it was above average. :drinks:

HARRYMPOPE
04-12-2012, 11:44 PM
Thanks,
This question came up while I'm trying to decide which of the two above listed molds to send off and have D.D. rings cut into their noses, since my Contenders have the usual T/C long throats and the 55-MX-3 Mold won't be out till way later this year.
Thanks all for your help

the MX3 62g is in.Did i send you Eagan samples.

george

HARRYMPOPE
04-12-2012, 11:56 PM
Wrong end. Accy comes from the back end, not the front.

Bill

unless the nose is the wrong size.I had 20+ plainbase 30 caliber's at one time and and swage/bump dies to alter nose and body shape.i could take about any bullet and swage the nose and body to the dimensions of the throat and it would shoot.If the body was short and the nose long and undersized no accuracy at all (regardless of nose shape).If the body was long enough and nose undersized it shot well.Best was body and nose tapered at 1 degree and engraving lightly.The two best bullets were the Pope311403 (blunt nose base band type) and the Modern Bond 311-1145 pointed 2 diameter with first band tapered to the nose.The SAECO #540 and #529 also did very well.

i agree with poppers statement

I am talking rifle bullets here.

George

stubshaft
04-13-2012, 07:10 AM
Wrong end. Accy comes from the back end, not the front.

Bill

True to a degree. If the Cg of the boolit is not correct then it will no shoot well. Case in point 225450 or many of the other sharply pointed spitzer designs, usually only produce mediocre accuracy at best.

Wayne S
04-13-2012, 08:58 AM
the MX3 62g is in.Did i send you Eagan samples.

george
George,
No you didn't send any samples, I'm wondering if the .725" OAL of the 62 gn. is a little long fora 1-12 twist ??

45 2.1
04-13-2012, 09:43 AM
strictly from an accuracy potential stand point, and everything else being the same;
weight, size & fit to the chamber/throat, length and % of bearing surface to OAL which would shoot smaller groups at 100 & 200 yds. A FN or a RN design.??

The above in blue plus a balanced properly burning powder charge with the MOST important thing being getting the boolit into the bore straight. Nose shape comes in after about 250 yards and further when it goes into the transonic range.

1Shirt
04-14-2012, 01:45 PM
Agree with 44Man. It all depends on what your rifle likes, and what shoots most accurately. Potentialy, the spitzer, or semi spitzer will shoot most accurately, but it is not always the case. It is a proposition of trial and error frankly.
1Shirt!:coffee: