Gents:
I am progressing to sample qualified bullets for my future gun,just from a statistical or experience level.Of course will have to experiment trial&error what the gun likes.

I have this big handicap in that I like the solid copper line of Barnes.I liked the bullet line for my 30/06.I shot 100's and 100's in my .338 Magnum without finding something that patterns even half way decent
moved to Noslers partition in desperation which work "ok"

To finalize the throat dimension I need to decide roughly what to shoot,so thats why I am requesting your help.
gun:.300 RemUltramag,26"barrel,12"twist,I am promissed it will shoot <3/8" match ammo

task: find hunting bullet options for deer/sheep at 100 to 500y,meaning I build the gun for the far shot but hate to giveup a lucky 100y range.

because the copper bullets are much longer then the convential jacketed lead bullets it seems unlikely I will even be able to try the copper type,as I have to decide on the best throat depth rather then a depth that takes all comers.

From what I know the contenders would be:
150-180 gr bullets with 165gr a happy medium and maybe the best weight.

bullets that I trust would be Nosler partition,It appears that Swift A-Frame are similar,dont know about the new Scirocco,almost looks like a Nosler Ballistic tip to me,maybe a stronger jacket.

I have a hunch these bullets hold up better than the "unibody" type like Sierra's gameking line

the problem seems accuracy coupled with best
controlled mushrooming over a wide range of energy

any and all experiences are appreciated

sheephunter

With the speeds you will be producing, you will stress a lot of lower end bullets like the Sierra's, Hornadys, and the like. You will undoubtedly be looking for the "premium" bullets to wring the best performance from the 300UM.
If it were me, I would look at the Scirrocco, Coated Xbullets, and even the ballistic tips for the game you are looking to kill. Deer and Sheep aren't that hard to penetrate, and the Ballistic tips in 30 Caliber and above aren't exactly built like varmint bullets in the weights you are considering. Also, the Scirrocco has been getting good reports. It is much like the Ballistic tips in appearance, but is bonded behind the polymer tip, which is supposed to make them perform substantially better. From reports I have read on the boards, they seem to accomplish this on most game admirably.
As far as the Nosler Partitions, what can I say? If you can find a load your rifle likes, your problems are probably over.
There are so many choices, the only way to find the one you like best is to try them all, but the choices above should be a good mix for the game you described. Every one should work just fine, just decide on which one and go from there. IMHO- Sheister

Thanks Sheister,
you are seconding my thoughts exactly.I am afraid the lead bullets with a thin copper jacket will not hold up or splatter on impact.Nosler partitions and A-Frames by their design have at least their rear portion protected.The Scirocco picture may indicate a thicker jacket at the rear end ,which might mean a controlled peelback/mushroom over a large energy spectrum.What is needed is practical exerience to verify those assumptions.
Part of my sobbing is that I feel I should build the throat to give decent results with above lineup.If I lengthen the throat to accomodate solid copper bullets,then the accuracy of the shorter lead bullets will suffer.If I then find out that the copper bullets dont shoot in the barrel c a 12"twist I am stuck c no bullets shooting to their best character.
A theoretical possibility might be to build the throat for "convential" lead bullets and try lower weight copper bullest of about same length.Because the copper stays together and should take all enrgy levels,a lighter bullet is probably feasible.
Again what would be nice is actual experience
proving or disproving these thoughts.
Gerald Schultz has an excellent educational web page on this subject for his HV bullets
but the bullet length/barrel twist scenario still seems to make it difficult to design for both type of bullets,copper and jacketed lead?
sheephunter

sheephunter, these are always the tough decisions and compromises one has to make when starting from scratch on a project. Picking a middle of the road compromise that will work for both is a crap shoot at best, but sometimes pays off. Unfortunately, I don't have the experience you are seeking for this project but I'm sure a couple people I know can help you out.
Over on 24hourcampfire.com is a guy by the handle of Big Stick. He is into Barnes bullets in a big way and has a couple big .30's, one being a .30 Souper, which should be at least the equal of your .300 UM in bullet requirements. He has much experience on game and shooting with these rifles/bullets. He has always been more than helpful in sharing his experience. You might want to post over there in gunsmithing or Big Game and give him a chance to explain. Don't be surprised if he mentions X bullets! - Sheister

Ross Seyfried and I discussed this very question the other day and his contention was the Winchester Fail Safe was the ONLY bullet he trusted these days for the fast new magnums...He is going to try some of GS bullets in the near future...

------------------
Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

We bumped into this problem of standard and short throats not working well with our older HP range of (smooth) bullets. They worke very well in long throats. With the HV range (driving bands), the intention was to have a monometal bullet that will shoot well in standard rifles without the need to have long throats or other modifications. If one builds a custom rifle and keep the throat standard or shorter, this improves the versatility of the rifle as a much wider range of standard bullets will work well in it in addition to our HV and FN bullets. Where a gun has a very long throat, concentricity of the bolt and chamber to the centreline of the bore becomes critical.

------------------
Gerard Schultz
GS Custom Bullets

Thanks,
Gerard- it seems that's the very answer to the problem on how to dimension the throat in a custom barrel,so it shoots solid copper bullets and also convential .If I understand you correctly,you solved the problem by coming up c the rings in your copper bullets?
I can see that there is less friction in the barrel with the rings,but fail to see how it shortens the optimal throat depth for the (longer) copper bullets

sheephunter

We have had great luck with the Scirroco's
On targets they are very accurate. Have had some pretty darn good groups with a custom 300 RUM.

On game, two Elk, one at 250 yds running, one shot through the front shoulders, folded up and stayed down.
Another standing at close to 350 yds, one shot, down to stay.
One bullet recovered from under the hide. aprox. 85% weight retention.

I am sold on them for the above reasons as well as thier most excellent B.C.

Celt

Sheephunter,

I've got a new Sendero .300RUM but have not shot it yet as I don't have a scope yet.

I've also been trying to decide on the bullets to use.

Here is what I've decided to try initially;

Scirrocco 180
Nolser Ballistic Tip 180
GS Custom 173

I will try some heavier bullets later.

------------------
To be old and wise.....first you have to be young and stupid!

Sheephunter,

I would definitely give Gerard's GS Custom HV bullets a try.

I would build your rifle with a 1:9 twist to handle the long monometal bullets.

The throat can be very short when using the HV (or FN) bullets because only the driving bands engage the rifling. The nose of the bullet just rides inside the lands. I suspect that a throat made specifically for the GS HVs or FNs would be so short you couldn't shoot other designs at magazine length.

But the bullets don't seem to be all that picky as to throat design. They shoot well in my factory barrels where no bullet reaches the lands.

Don

[This message has been edited by Don G (edited 11-11-2001).]

Sheephunter,
Don has the right answer. With a smooth bullet, the nose is at barrel groove diameter well ahead of the case. An HV nose is at bore diameter and the front driving band is the first thing the rifling will encounter as the bullet steps out of the case for the wild ride. It makes it very easy to get exactly the same jump from case to barrel with HVs because the engagement of the rifling is at precisely the same point on every bullet. Very small changes in the ogive of smooth bullets can change the distance off the rifling by large enough amounts to become a significant variable. Variables cause groups to open up.

Old Sarge,
If your barrel is one in nine, the 173 gr HVs will work well, if it is one in ten, stay with the 160 gr HVs. I have come to mistrust what the factories say the twist on a barrel is, and rather measure it myself. We have seen a Schultz & Larsen rifle that was factory stamped twist one in 12" and it turned out to be 14". 7x57 barrels from one particular manufacturer measured over a period of three years, varied from one in 7.75" to one in 10.5"!! They are no longer making rifles. It seems that only the manufacturers who use hammer forged barrels have a good measure of consistency on twist.

------------------
Gerard Schultz
GS Custom Bullets

I'd go with the standard length throat. This is the type of thing that you will hear so many different opinions you will wind up dazed and confused. You either build the rifle to shoot one particular bullet or weight or build it to shoot a certain range of bullets.

Pac-Nor rebarreling offers mostly standard length throats in their chamberings. (they can lengthen a throat using a special throating reamer.) By going with a standard throat you will be able to choose from a wider variety of bullet brands. Ernie(shop foreperson) from Pac-Nor was telling me of a recently rebarreled 300ultra which was shooting under .5" with the bullet seated .060" off the lands. Chris Dichter(Pres. of Pac- Nor) recently built a 30-338 for his son which turned in a personal best of .179" grp using Barnes X bullets! Another great barrel maker and long range shooter Boots Obermayer states "alot of shooters like to shoot their bullets off the lands to obtain accuracy, this leads to pressure problems and greater velocity deviations. I have a 6.5-308 which is still delivering excellent accuracy with bullets seated over .2" from the lands."

I own 2 Pac-Nor barrels which deliver sub .5" grps using standard length throats and bullets seated over .060" from the lands. I own a 3rd Pac-Nor barrel chambered by Darrel Holland with a short length throat which also delivers sub .5" grps but guess what? With Nosler 95gr Part it will only deliver tight grps with the bullets seated .050" off the lands.

My advice is to go with the standard throat and be done with it. It will offer greater versatility. Pick a bullet that you like and try different powders and seating depths. If you are still not satisfied then try another bullet. My 2 cents worth. sure-shot

Sure-Shot:
If I would be intelligent I would not even question which throat dimensions to use- but I am a tinkerer at heart- who after tinkering usually sees that "average" = best,for reasons you state.This is not all in vain as one gets an understanding of the problem and a feeling what individual bullets perform.
Given this scenario I hope to use "standard throat" although my gunsmith requests some cartridges + bullets,so it looks like he will
accomodate all bullets I decide to deliver to him.I dont want to cast the net too wide
as accuracy probably suffers without need.

I very much liked the news that Scirocco bullets held up for elk.They seem to have a thicker jacket.
My thinking is to design the "standard throat" for known hunting bullets in Nosler partition,Scirocco,possibly A-Frame.These seem to be of stouter construction then the rest.Then try Barnes coated XBT or GS HV bullets that fit and fly in this configuration.In other words design for convential lead,hope for better solid copper.

Anyone has load data for the Scirocco together with chrono data?

thanks all,
sheephunter

[QUOTE]Originally posted by Gerard:
....etc.
Thanks Gerard,again.
It appears you know what you are talking about,while I have to study the bullets.
It appears the HV bullets "get away" with convential throat,rather then long throat-because they have weight in front of the rings and throat is measured from the rings +setback?
One question regarding those rings-purely unproven and desk-opinion on my part:
I always want a "smooth projectile" I dont even consider bullets c a cannelure.
Anything that creates turbulence slows the bullet or makes it fligh less straight-or both
Now you construct 4-5 rings,the turbulence at speed ought to be considerable.
I wonder what speed and pattern difference you have from smooth to ringed at distances of 250y and beyond.
In other words this might not show up at 100y
sheephunter

Sheephunter,
When we were experimenting with the HV concept, we noticed that the trajectory of a bullet improved as we added the driving bands. Going back to when I was involved in motor racing, I eventually figured it has to have something to do with a thing called boundary layer. In consulting with an expert on fluid and gasflow technology, he confirmed this. Once the bullet has exited from the muzzle, it no longer has bands on it, but a series of tiny buttons from the rifling cutting through the bands. This apparently reduces the boundary layer adhering to the bullet as air flows over the surface, and it makes a smaller hole in the air and flies better. Weird, but that is the explanation that was given to us.

------------------
Gerard Schultz
GS Custom Bullets