Brent, I'm looking at the .300ultra. Went and checked my reloading bench and found a box of 180g Balistic Tips. From my calculations, if I seat the bullet flush with the neck junction, the O.A.L. would be 3.905". With the factory chamber in the rifle a O.A.L. of 3.805" will set the bullet against the lands. I'm curious on the difference in accuracy between seating the bullet at the neck vs .100" deeper into the neck, say out to 1000 yards. Also, is the extra case capacity of the .300 super improved usable (keeping the pressure under 65,000psi)? Wondering what your seeing shooting over your 43P.
I checked my records and found the 180 BT’s OAL to be 3.801” on contact, and measured at the ogive with a Stoney Point comparator it is 3.159”. That is very close to yours.
The boat tail on the Nosler is .100” long, this part I try to leave below the neck junction for best bullet retention, this way I have a 3.75” OAL approximately.
Most of the rifles I have worked up loads for have shot better with bullets seated close to the rifling, except my 416wby, I have not had good luck with it near contact with the “few” loads I have moved forward after they shot good, groups just went south in a big way.
I have not noticed psi running up “on my guns” seating bullets closer to the lands, the opposite really, I have seen psi move up by seating them deeper in the case when backing away from the lands and get less or stay the same when moving closer to the lands. Keep in mind, I have not specifically tested for this, per say, just an observation I have made while adjusting depth to better tune the load. I believe the case capacity increase is offsetting the psi increase when seating the bullets out more, often to a point it actually goes down 2 or 3k psi.
As to the extra capacity being usable, I would say any extra capacity is usable, either by way of increasing velocity or by way of reducing pressure. The question, I believe, is weather the advantage is great enough to the individual to warrant the additional cost of investing in the non-standard equipment to make use of it.
Improving the 338 Lapua case and necking it down, as you see, would gain about 5 grains capacity. This, for me, is about the least gain I would like to see to make it worth it, on that basis alone. But considering the fact that the Lapua brass will out last the rest, probably two to one, quality is very consistent, the case OAL is shorter, the case head is .050” thicker and I’ll be using the reamer to build the 338 Lapua Imp of mine shortly, I just went with it.
On the other hand, one has to figure what their actual cost of brass is. In Boyd’s case, where he gets 300 Ultra brass by the bucket load, it wouldn’t make much sense at all to go the Lapua route at all.
Most of my shooting experience has shown that accuracy is usually below max load by a grain or three, so I will likely be getting a bit more velocity at he same reduced pressure than I would using the 300 Ultra in an equal length barrel. The 5 grains extra capacity is probably worth maybe 8-10k psi, maybe more. The velocity potentially gained would seem to be quite a bit higher as well, but is not always true, but they do run hand in hand.
Pressure runs “more” parallel to velocity than grains of powder often does.
I have some good loads that I’ll be moving closer to the rifling to see how they do. I usually check them the other way around first, it just worked out the opposite this time because I was starting with some I had loaded to fit the mag and just continued working up from there.
I shot some 180 Ballistic Silvertips that were seated into the lands out to 1000 yards a few weeks ago, they were shooting extremely well. The Nosler BT has not proved to do quite as well with this powder though. The 180 Scirocco and the 180BST did about the same, group wise with the same load.
I might just do that. I don't want everyone to think I'm THAT much of loser when it comes to reloading. I own and have read Glen Newick's book several times, and I do understand some of the techniques I SHOULD be using. I have just never invested in the gear required, and was always satisfied with the 1/2" or less groups I get in nearly all of my rifles. Now, to get there, I have spent hundreds of hours pillar bedding, opening up barrel channels, adding pressure points, rebedding, fussing, cussing, etc. I've also spent thousands of dollars on trigger jobs, new chambers, recrowns, action truing, blueprinting, etc., etc. New barrels, better dies and better loading gear probably would have been a better place to spend my money, but just like good optics, I had to learn the hard way. Once I put my first Leupold on, I never went back and except for one, all my scopes cost more than the rifles they are sitting on, and the one that's cheaper is only about $100 off! I think I'll contact Neil for my 6-284's too. I'm building two - one walking varminter/carry rifle on a Model 7 and the other a 12# gun with 30" barrel. If they are both cut with the same reamer, can I use the same dies even if the throats are different lengths?
I'll urge you to call Dave Kiff again, just because he's a pleasure to talk to and so helpfull, not that anyone here minds helping at all, and likely enjoy it. [img]images/icons/smile.gif[/img] I guarantee you, he will make this all too easy for you. [img]images/icons/wink.gif[/img]
This is what he suggested to me along the same line. The first (main body and neck)reamer, have it made with the neck and throat already part of the reamer, this will do the complete job on the shorter throat chambered rifle($135), the next thing you'll need if you want a longer throat, for a longer bullet or OAL on one of them is a seperate throat reamer ($66). That is about it. The dies will work with both, regaurdless of the cartridges OAL if the case itself is identical.
If one is a tight neck, needing turned cases, and the other is not, you can have Neil give you bushing for both neck dimentions and you are off and running. [img]images/icons/wink.gif[/img]
If the necks ar going to be different, have Dave design the reamer with the smaller neck on the main reamer and tell him you need a neck and throat reamer in one for the larger neck chamber, cost is the same.
I'm not sure if you mean the necks will be different or the throat though. The throat just has the rifling removed for the length of the bearing surface of the bullet on the loaded cartridge, and the leade just tapers this into the rifling, normally at a 1.5 degree angle, where the ogive finally makes contact with the lands. You see, the "throat would have no bearing on the dies sizing the case, as it is beyond the chamber, starting where it ends.
Dave will have knowledgable suggestions as to what works and what doesn't and save you alot of headache durring the process I assure you. He is there to sell you the right tool and he aims to please just like a good smith, a super good guy. [img]images/icons/smile.gif[/img] It sounds like you are going to have a "couple" MORE nice rifles when you are finished here.