Bcraft1111,
Fist off, welcome to LRH. Good to have you with us /ubbthreads/images/graemlins/smile.gif.
Well, I am not a huge fan of the Lazzeroni rounds as a hole, on paper performance numbers are pretty impressive but unless you use his rifles and bullets, you will not reach these levels.
In your case you are using his rifle and loads. I have always found case tolerances to loose with the Lazzeroni brass to produce consistant results at long range. While some has been very good others have been very bad and you never know what you will get from one box to the other and for +$2.00 per case, that is simply not acceptible in my opinion.
As far as your velocity lose, its hard to say for sure, loosing 400 fps is a dramatic velocity loss for sure.
The problem with some barrels and using Moly coated bullets or any other coated bullets for that matter is that sometimes it take a few shots for the velocity to stabilize and get consistant. This is one reason I do not like coated bullets except for rounds like the 50 BMG where controling copper fouling is a must.
I would say there are several areas to look at.
First off, with 800 rounds down the tube, you may or may not have a throat erosion problem. Really depends on how those 800 shots were fired. IF you kept the barrel relatively cool during shooting, I would be suprised if you were even half way to the end of your barrel life.
Course with a case this size, if the barrel did get heated up, and was still shot when hot, the throat may be eroaded quite badly.
This is the most obvious reason for velocity loss of this degree but it does not happen all at once.
Some other factors that may be in play are:
-Are you using a different lot of IMR-7828 then when you developed your first loads? If so this can often change velocity a significant amount in a case this large.
-Are your X bullets being seated to the same depth as your first load. Not measured with Over All Length but at the full diameter of the bullet at the beginning of the ogive.
The X bullet is extremely sensitive to seating depth, any solid bullet is. Even a change of .020" can dramatically drop or raise velocity(pressure). Another reason I do not use the X bullet, they are simply to finicky to shoot.
Lot to lot variations in bullet shank length are common to a small degree, this can effect the distance from the full diameter of the bullet to the origins of the rifling, changing pressures from one pot of bullets to another.
In my honest opinion, using a 150 gr bullet in a 30 cal magnum case with a case capacity of +100 grains is really a waste of alot of horsepower. Sure over 500 yards they are flat shooting as hell but past that they really start to drop off.
If I were you, before I did anything as far as rebarreling the rifle, I would get a box of 180 gr Accubond bullets and test them with H-Retumbo. My brother has the Sako in the Warbird and with this powder and bullet was able to hit +3500 fps with groups ranging from the 1/2 to 3/4 moa range with great consistancy.
Big cases are quite ****y with light bullets driven very fast. It seems anything of a weak link is magnified dramatically with a light bullet driven to very high velocities.
Whereas the heavier bullets can be driven to very good velocities and just seem to settle the big cases down as far as an accuracy standpoint is concerned.
I have never found the X bullets to be accurate enough and consistant enough for me to recommend them to my customers for use in the rifles I build for them.
For a rifle like yours that cost what it did to only shoot in the 1 moa range would just about make a guy sick. This is not a shot at you at all but are you being effected by the recoil and blast of this big 30 magnum? Does teh rifle have a brake fitted to the muzzle?
All of the things I have listed would probably not equal a 400 fps loss in velocity but the drop is just over 200 fps from your 3493 fps to your 3729 fps average to start with. This could easily be a result of a combination of the above listing.
To be honest and you probably do not want to hear this but personally, if you rebarrel the rifle, I would drop the Warbird adn go with something else. Even the 30-378 Wby or a 30-338 Lapua Improved which is basically a 7.82 Warbird would provide much better consistany from a brass stand point and its cheaper to buy as well.
Still before you do anything I would highly recommend dropping the X bullet and testing some Accubonds or something on that line. Load them off the lands about 0.010" to 0.015" to start with and then you can adjust the seating depth from there to see how they respond on target.
You will not get the screaming velocity with this bullet weight but if your rifle did not hit 3550 fps I would be suprised using Retumbo. Also, if your rifle does not shoot them inthe 3/4 moa or less range I would say its time for a change in barrel.
Couse if your rifle has never shot better then 1 moa, it may need to be torn down adn rebuilt with a quality accurizing job.
The cheapest step is to try a new bullet, then go from there is that does not work.
If it comes to rebarreling the rifle, find a smith that builds extreme accuracy rifles for a living. There are several on the board alone that do this including myself.
I assure you, that if you ordered one of my rifles it would not leave the shop until it was cutting 1/2 moa groups and I know that is teh standard from the other smiths on this board as well. You should not have to settle for 1 moa groups from a rifle that cost that much money. We could build one for much less that would shoot far better I assure you.
Good Shooting!!!
Kirby Allen(50)
