High extreme spread

[D Scott]

I am reloading for a Savage LRP in 260, I have been shooting Noslers custom comps HPBT in 140 gr, at first I was getting around 20 fps ES, but now after several reloads on the brass it seems my ES is starting to grow, I have changed primers, CCI BR2, federal Gold match, and Winchester large rifle primers, the CCIs are the best,

aside from the differences primers can make, what else in the brass prep dept would influence ES, I am getting over 50 FPS ES now and I am seeing the increased vertical dispersion downrange over 4 inches at 600 yards, I did get some ES down at 6 FPS with hornaday A max , with the same brass prep method

Have been getting groups at 100 yrds in from 1/2 in to 5/8 inch

Usiing Forster comp FL size and seater dies, I FL size each time, with expander ball

Tumble with SS Media for 2 hours or so
using 4831 sc 44.8 gr / nosler 140 CC HPBT

seating depth doesnt seem to effect ES, or accuracy

using a magnetospeed chrony, it does cause POI shift, but would it decrease accuracy ? since its attached to the barrel ?
thanks in advance , any feedback or advice would be appreciated, Scott

 

[barnesuser28]

You need to anneal your brass, the necks are getting hard and brittle, you will start to split them soon if you dont anneal.

 

[D Scott]

I have been annealing every 3-4 th firing per the method on accurrateshooter, use the tempil 650 degree paint, spinning in a drill /socket, I have no pressure signs or any split necks some brass 12 x

 

[Gene]

Anything that relates to pressure differences, can explain high ES and/or SD . Neck tension is most important, then OAL. I would throw away the expander ball, get a bushing die, and three bushings to experiment, starting about .003" less than loaded round diameter. Then you also need a bullet comparator. You can find all of these in the Sinclair catalog or web site.

Expander balls pull the neck erratically and are often the sole cause. And your accuracy seems pretty good. Forget about the ES and look at consistent group size.

 

[royinidaho]

Use Bore Tech Eliminator and see what happens.

 

[MagnumManiac]

I am reloading for a Savage LRP in 260, I have been shooting Noslers custom comps HPBT in 140 gr, at first I was getting around 20 fps ES, but now after several reloads on the brass it seems my ES is starting to grow, I have changed primers, CCI BR2, federal Gold match, and Winchester large rifle primers, the CCIs are the best,

aside from the differences primers can make, what else in the brass prep dept would influence ES, I am getting over 50 FPS ES now and I am seeing the increased vertical dispersion downrange over 4 inches at 600 yards, I did get some ES down at 6 FPS with hornaday A max , with the same brass prep method

Have been getting groups at 100 yrds in from 1/2 in to 5/8 inch

Usiing Forster comp FL size and seater dies, I FL size each time, with expander ball

Tumble with SS Media for 2 hours or so
using 4831 sc 44.8 gr / nosler 140 CC HPBT

seating depth doesnt seem to effect ES, or accuracy

using a magnetospeed chrony, it does cause POI shift, but would it decrease accuracy ? since its attached to the barrel ?
thanks in advance , any feedback or advice would be appreciated, Scott

I have a question, you mention your group sizes being 1/2-5/8", has the ES change effected your groups?
If it hasn't changed your group size, you haven't said it does or not, then why worry about the change in ES.
I have had an ES of more than 100fps that shot into .3's, I cannot explain how this occurs because it goes against what we all think would be a very inaccurate load, my theory is that for some reason the bullet is being influenced by barrel whip alone and other forces are not influencing the outcome in any large way, obviously the difference in velocity is having very little effect on the bullet, even in regard to POI with no stringing evident. This was from a 10 shot group, shot in 2 5 shot groups, I didn't notice the ES until AFTER I had shot the 2 groups!
Anything attached to a barrel will change POI, ask anyone who shoots with a brake off the bench, and then hunts with it off.

Cheers.
gun)

 

[backwoods83]

Didn't see you mention what kind of brass you are using, I have loaded 400 rounds of 260rem, 200 for 2 different friends, they bought lapua, lapua is good brass but these 400 happen to be the worst lapua brass I have ever loaded, the neck tension and thickness was so uneven I wanted to trash them. When I load them again I will turn a couple thousandths off the necks and use a .292 bushing after annealing. I hope this isn't your case, its a pita! One more side note is that the Nosler custom comp bullets tend to shoot very well out to 600yrds but the meplats are horrible and the bearing surface length can vary almost .040" in 1 100ct box. And as Roy said, take a little copper outta the barrel!

 

[D Scott]

the accuracy is always very good from 100-300 yards, its when I start shooting beyond 600 and up to 800 yards I see the lower velocity rounds hitting lower, and vice versa, Im using rem brass, havent tried anything else yet, I have bee meticulous with being consistent with my procedure, I will try the bushing die next and maybe some new brass, thanks for all the feedback, any one done any work with hornady bullets ? Scott

 

[FAL Shot]

If you chronograph on a day with widely varying light conditions, it will affect the accuracy of chrono results. I learned to chrono ammo of a sunny day with no clouds between chrono and sun. Also, a high summer sun shining on the chrono sensor will affect the reading as well. A cardboard shield taped up high enough to just keep out direct sunlight from entering the sensor cavity will solve this problem.

I have seen chrono readings jump about 100 FPS between direct sunlight on the chrono and then a dark cloud passing over. I use the Shooting Chrony F1 Master, and it will apply to all similar Shooting Chrony chronographs.

Amount of cloud cover is not consistent, but a bright sunny day is consistent. Also, the sun should be 30 degres or more above the horizon to have a consistent light source for the sensors. No chrono readings taken early or late in the day for me.

To test a chrono for consistent readings, use a high quality precharged pneumatic air rifle and shoot weight sorted pellets through it. The air rifle should be fully regulated or self regulated with fill pressure set at best accuracy range. With my BSA Lonestar .25 cal air rifle using JSB pellets, a string of shots will be within about 3 FPS range. High quality PCP air rifles are amazingly consistent in velocity if the pellets are match grade. JSB pellets are usually within about a .1 grain spread. So good that I quit weight sorting them. So buy a can of JSB pellets and have somebody with a fully regulated or self regulated PCP air rifle shoot over your chrono.

Self regulated means the velocity is consistent over a range of shots, maybe as many as 10 in my air rifle, if you keep fill pressure in a narrow range. Hunting rifles tend to be self regulated while target rifles tend to be fully regulated. The fully regulated rifle suffers power loss as the regulation is set at a much lower pressure than fill pressure, but the pressure to the barrel is constant shot to shot until fill pressure drops to regulation pressure. A regulator does not increase pressure, just drops a higher pressure to a set lower pressure. Hunters need full power, so something like a Benjamin Marauder is self regulated. An exception is the Benjamin .357 Rogue. It has an electronically controlled air valve that lets you set energy anywhere you want it, provided you have enough fill pressure, all the way up to 250 FPE, the same as a .38 Special revolver. Definitely a hunting air rifle, designed for animals up to deer size. Find a guy with one of those, and it will be a very consistent shooting rifle that is useful for chrono testing.

Now, after confirming you have a consistent rifle and round, shoot over your chrono on a day of sun and clouds and watch the readings change quite a bit. In this case, it is your chrono and not your load that is inconsistent.

 

[backwoods83]

Yep 123 and 140 amaxs shoot awesome over H4350.

 

[Trickymissfit]

I have been annealing every 3-4 th firing per the method on accurrateshooter, use the tempil 650 degree paint, spinning in a drill /socket, I have no pressure signs or any split necks some brass 12 x

650* is a little too high for brass annealing. Try bringing it down to 500*, and even 450*. Also get yourself a pair of welder's glasses! How far back you take the heat into the case is also important. I prefer to go back about midway into the shoulder, as by the time the quench happens the heat has moved to the shoulder body junction point. Heat tends to travel in brass and even aluminum very fast.
gary

 

[D Scott]

using the magnetospeed I dont have to worry about light conditions, I will do more research on annealing,

at Tickymissfit do you have any data/evidence to support annealing at any given temp ? the reason I ask is b/c I read An in depth article on accurateshooter.com andthey were suggesting 650-700 range

 

[D Scott]

I am also using a RCBS hand priming tool, any thoughts on primer seating ?
I appreciate all the feedback thanks Scott

 

[D Scott]

also any feedback on who does the best job on a bushing die ? wilson? redding ?
do I need to watch for"donuts" using bushing dies ?