I spoke to an aquaintance of mine yesterday and he has had a 30/378 for a while. He is using H1000 and our Australian 50 BMG powder. But his loads are only around 3200 with 180s. He has found the accuracy to be very good and consistent and just a lot easier than other calibers he has used. I have also found this to be the case when using big cases for the caliber, like the 460 Wby, but loaded back a couple of hundred feet per second. Users of 416 Rigbys loaded back to 416 Remington also seem to get very good accuracy.

So, my thoughts are that if you want say 300 Winchester performace then you might be better off with a 300 Rem Ultra with backed off loads.

This would also produce very good case life and possibly superior barrel life when compared to the smaller case loaded to full pressure

What do you think.

Mike

[ 07-05-2002, 04:22: Message edited by: Mike375 ]

In my own experience, the smaller bores needed full throttle loadings before accuracy became truly good. Large bores seem to respond well to reduced loadings, much to my shoulder's delight.

John,

I would certainly agree in general with what you said.

However, rifles often shoot well at a top load and a lower load. Good accuracy at the lower load level also seems to be less dependent on both barrel and bedding quality. Hnece many shooters find their "out of the box" factory rifles shoot best with lower loads.

Mike

I have found that extremely few of my rifles, or handguns, shoot most accurately at maximum loadings. Backing off a couple of hundred feet per second always tightens the groups and extends barrel and action life.

[ 07-05-2002, 05:08: Message edited by: ricciardelli ]

Principally because I've always sought the max velocities in the medium bores, my experience has been that the best accuracy is either at max published velocity, or higher. But then I tend to use slower powders to 100% density, or more.

In very few small bores am I able to find accuracy loads below maximum published velocities, but then I think this is because I'm inclined to the slower powders for the case therefore skewing my results. I see too many shooters at the ranges I frequent who get phenomenal accuracy from very fast powders which don't fill the case. I therefore believe it's greatly dependant on "operator", and load development.

Bob,

One of the most accurate loads I have in a 375 is 39 grains of H4227 Extreme and the 220 Hornady Flat Nose.

I susopect that load or similar would probably be even better with a superior projectile.

That load is very mild pressure.

Mike

When in comes to the most accurate load in the three main cartridges that I load, maximum velocity and accuracy vary quite a bit. In my 300 wby, max. loads always give me the greatest accuracy. In my 460 Wby, a grain or two below max. produces the best accuracy. And in my 6.5x55, by far the most accurate rounds are medium to light loads. I have tried increasing my "perfect" load by only 1 grain and the accuracy was terrible. I went from 2-3" groups at 200 yds to a pathetic 10"+. It was amazing what just 1 grain difference will do!

In short, I think that you just have to work with powder and bullets with each gun until you find the perfect load.

Shawn

In my 300 ultramags and 7mm stw's I have noticed no difference in accuracy between max loads and reduced loads.

Mike I am yet to try reduced loads, I am sought of always caught up in chasing a little more velocity out of my rifles if anything.

I ain't real sure what is big bore, and what is small bore, but my 338 Mag shoots 200 grain Hornady Flat Points and Lee CGC (220 grains?)in a tight little wad at about 1928 fps.
Little deer around here with our close shots don't notice the reduced loading, they just die!
LouisB

Have yet to get a load to shoot well using the RCBS 200 grain CGC FP bullet.


[ 07-06-2002, 01:53: Message edited by: TCLouis ]

I haven't reloaded yet so I don't know.

One question I have is: What causes "detonation"? I thought it was from having large cases that were not loaded up enough.

I agree with John S. My best loads are max in my 300 H&H, 300 Win, 338 Win. and that ilk....the bigger cases than say the 340 Wby and up seem to shoot better with a somewhat reduced load and that should apply to the 300 RUM etc. Maybe. but it mostly depends on the particular barrel I suspect.

Mike,

The only comparison I have is my 35 whelen ackley now re-chambered as a 350 Rigby. As a whelen ackley, it simply refused to group unless loaded hot, pushing 250 gr to 2700 fps. With the rigby chamber, it shoots accurately at 2600-2700 fps, which is ~100 fps below max velocity, and doesn't seem as finicky.

I believe the largest factor as to the increased accuracy is Mr. Ricks quality chamber job, crown, and trueing the accuracy.

I have thought this one through a few times, and wonder if it is'nt backing off of the recoil that makes the rifle shoot a bit better in most hands..In other words if you back off of velocity, you back off recoil, and most shooters think it shoots better,but in reality they shoot better because of the reduction in recoil..Even in experienced hands, reduction in recoil will helps with little groups...

Lee,

No it is not recoil, well not only recoil.

For some reason lower loads seem to better from crappy bedding and crappy barrels.

A perfect example is the 22 PPC and 22/250.

At our range you will often see 22 PPCs going at about the same speed as factory out of the box 22/250s. But that is because the owner of the 22/250 has backed off loads since they shoot whereas the 22 PPC shooter is using a bench gun and is loaded to full power.

Mike

There was agreement here in another thread that a well put together rifle will shoot almost any load well.

The history of accuracy in Remington 40-X's shows that the more powerful cartridges don't group quite as well. I guess the groups would be at 100 yards.

Over at the 24 Hour Campfire Ken Howell has his .220 Howell and maybe other cartridges. He claims better barrel life from a low pressure load in a 30/06 case necked to .224" I have not followed all of the details of accuracy with his concept.

Mike,
I actually believe what you say is true, I think there are 2 comfort zones for a rifle, one high, and one low. What I was saying is I believe a lot of the guys that have the big bangers simply reduce the loads, and say it shoots better, because it does not hurt as bad. This does not apply to the more experienced guys..

Well guys, the barrel is vibrating, and for best accuracy what you want is for the bullet to exit at one of the times when the barrel tip is changing direction. At that moment, small differences in exit time result in the smallest changes in point of impact. This is assuming your barrel is vibrating in a mode where there is a "zero velocity" node, of course.

In such a case, there will be many such velocities that maximize accuracy. Trick is to find a very consistent load that causes the bullet to exit at one of the right times.

Pertinax

Let me add that while there will be "many" such exit times, the associated velocities may not be acceptable. Thus, you may only have access to one or two (or zero!) such nodes. It all depends on the frequency of vibration.

Pertinax

Pertinax is correct about barrel harmonics. A have Sendero 7 mag that I did an in depth study of barrel harmonics. I found there were several accuracy points, approx every 71fps change from 2700 fps on up (150g nosler bt) to 3000.

2728fps
2797 +69fps
2869 +72fps
2940 +71fps
3011 +71fps

Each velocity "sweet spot" gave me 0.30-0.33" groups at 200yds. In between these velocities groups were in the 1" range. BTW, this rifle was extraordinary when new, as the throat only measured 0.010" of freebore from std oal with the 150g nosler. Typically, a non police rem 700 will measure around 0.300-0.400" freebore for magnum chambering. Clearly this lack of freebore lends to greater accuracy, as even factory Fed Premium ammo is sub 1" at 200yds. Pressure signs are non-existent at any of the loadings I used.

Clearly the velocity to use in the field would be the highest, 3011fps, as it will cheat the wind better. Above 3011fps gave me erratic performance, which confirms others comments about max loads being inconsistent. This was also my experience. BTW, Factory loading for this bullet is 3110fps.