Has anyone else gotten this type of velocity from a straight Lapua? I am sitting with 92 grains of R-25 and RG Henson's 265 bullet leaving the muzzle at 3267 with a standered deviation of only 4.3! again the books say that this is impossible and I only have a 29 inch Schneider p5 on the rifle. It shoots good but, not great yet, into the .6 and .5 but nothing spectacular. i have only had 20 pieces of brass to work with so load development and accuracy are slow in coming. I will get the gun to shoot better once the 100 pieces of Lapua brass gets here. I have a 6.5 that does the same thing and it also has Gary's barrel on it but it is only 23 inches long. I can push 107 smk's at 3600 fps with no trouble. Any of you guru types out there have any info on the P% being so much faster than other barrels?
Last thing, I have always had trouble getting great accuracy out of long for caliber bullets, like 140 vlds for the 6.5 and the 300smk for this rifle. I have a 1/8 for the 6.5 and a 1/9 for the Lapua, but always the lighter bullets shoot better, is it just that the heavy for caliber bullets are in the bore longer and I am screwing things up just prior to exit or is there something else that I am missing? I can shoot lights out with 225s in the Lapua and the 107s shoot to .3 without me trying anything fancy. I would love to know if there was a trick to this, because I have had the same issues with heavy bullets in the 223 AR's I can get 3100 out of 69 and 70 grain bullets but the accuracy is just crap. not only that but no gun i have will shoot Nosler Custom compatition bullets.
I can't say velocity wise for that cartrige, but I have seen a couple barrels shoot100-200 fps faster then others of similar brand and length. Mainly factory barrels. I have a savage model 10 predator with a 22" barrel that will shoot factory 40 grain vmaxes at 3975, my buddies is 3805. As for the 300 smk I know a lot of guys shoot 1-10 twist or 1-9.5. I think the new berger 300 are made for 1-9 twist. Don't hold me to that. But if so you you might want to give those a try.
I too believe in barrels as having varying affects on velocities. I stated that the 107 Sierras are clocking 3500 and can be pushed to 36 if needed, but the awesome factor comes when you get this kind of velocity with hunting bullets such as the Bergers. they are also showing signs of 150 to 200 fps faster and even tighter grouping. The 120s are shooting super and as far as we can tell their 140 reigns supreme through this rifle. I have not had the opportunity to test the 130s as they are newer in offering I think, and the only other competitor is the 142 from Sierra, but as they state this is not a hunting bullet, and the Bergers defiantly are. I am holding my breath for the new 338 that they are in line to offer and would like to see something in the 275 and 285 range as well as their version of the 300. I have now officially adopted Bergers for hunting apps exclusively, but have to hand it to Sierra for their affordability and consistency.
I think the new berger 300 are made for 1-9 twist. Don't hold me to that. But if so you you might want to give those a try.
Berger Ballistician Bryan Litz is saying 1-10 for the upcoming Berger 300g .338...should be something!
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In my experience developing loads for many 338 Lapuas as well as the 338 AX which is an improved version of the Lapua and from what I have seen, your well above what is normal for this bullet in a standard Lapua. Could be a fast barrel but even then your a bit high. FOr a standard Lapua, I would say 3100 fps is about tops of what I have seen with this bullet.
The main problem with custom rifles that are built correctly will not show normal pressure signs, especially when combined with a strong case such as the Lapua which will easily handle around 70,000 psi before the primer pockets loosen up.
An example of this that I always tell my customers is about a customer of mine that I built a 257 STW for on a fully trued Rem 700, 30" lilja 1-10 Lilja barrel. The load data I sent home with the rifle was with a 100 gr BT at 3850 fps which I have found to be about the top for STW in Lilja barrels.
Well, he had gotten on line and found some reports that the 257 STW is a 4100 fps chambering with 100 gr bullets in a 28" barrel that were posted by a rifle builder that I personally believe is very irresponsible. Anyway, my customer started building up the powder charge and sure enough he got to 4100 fps and was very happy, that was until he resized the cases he had used to develope the loads. The primers simply fell out of the cases when he tried to prime the cases. He came to me pretty upset as he had shot over 50 rounds of brass before he found the problem.
He commented that something was wrong with the rifle as the bolt could be opened with one finger on a fired case and extraction was effortless as well. I explained to him that this is common with a trued receiver as they do not show the normal tight bolt signs from high pressure like you would in a factory rifle.
After a bit more education, he decided to go back to the 3850 fps load and not look for greener grass elsewhere.
My point, do not think that if your getting velocity levels that are far over what is normal for a given chambering that you are getting these velocities with normal pressures. Velocity is simply a function of pressure behind the bullet and the time this pressure acts on the bullet while its in the bore. There are other factors but simply put, if your getting very high velocity, its mainly a result of higher pressures.
I once had a Ruger M77 MkII chambered in 7mm Rem Mag. I developed a load with the 140 gr Ballistic Tip using Reloader 22. I was looking for pressure signs and had none in any way so I kept increasing the load looking for signs that I should stop. I got to 3450 fps and still had no pressure signs at all, even primer pockets were snug still. How could this be. I was pushing a 140 gr bullet as fast or faster then even a 7mm RUM factory load.
After thinking about this for several days I decided it was wise to drop back to 3300 fps and be happy. Your chrono is your best friend in predicting pressures, even more so then trying to read pressure signs from your rifle or brass, pay attention to what your chrono is saying. An extra 100-150 fps is not worth the strain you are putting on the entire rifle system for that extra velocity.
Just my opinion from what I have seen with similiar handloading results.
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