I was considering how much runout I should consider to be tolerable for my hunting rounds and on a lark decided to see how much runout was in the factory rounds of my son's .260 Remington Premier Core-lokt Ultras. I had a new box of 20 and the average runout measured with an RCBS runout gauge was (drum roll, please..............): .0065". They ranged from a high of .012" to a low of .003", most between 6 and 8 thousandths. I was mildly surprised. I'm curious what your thoughts might be on the results of my, admittedly unscientific, little sampling of these factory cartridges and what you consider to be a tolerable amount of runout for hunting loads.

I'm not at all convinced that (so called) runout is worth measuring at all.....

Many things contribute to accuracy but such things as we might think are important just are not so much as we think they are.....run out is one of them. Standard deviation of velocity is another...how many folks have worked for small SD and achieved no good groups at all???

Add to this such things as flash hole deburring, primer pocket uniforming, neck turning, ultra precision case trimming, and several more common practices just have never been shown to be valuable.

If reloaders would work to find a bullet that fits a guns needs and then a powder that pushes it well he has most of the issues licked. Most often the balance of things he can do add up to such miniscule gains that they aren't measurable without a very lot of statistical proofs.

When the game changes to benchrest I'll concede the point as even .010 improvement in groups can be measured by some of the dedicated nuts.

For hunting rifles we would all do well by simply concentrating on good bedding of the rifle, finding a good bullet and powder to run it and work on our personal technique of shooting.

I have runnout gauges and do strive to make as straight of ammo as possible. BUT in my hunting rifles I'm with Vapodog to the "t" on what he says. In my book about 98% of the accuracy potential of a normal hunting rifle at ranges to 400-500 yds comes from how well YOUR GUN likes the bullet and powder load pushing it. The runnout you are seeing in the factory rounds is acceptable for the hunting rifle.
There are plenty of guns out there that will shoot sub MOA with ammo that's visually wobbly when rolled accross a table. That's far better than most guys can shoot in the field.

Hey Pearson

I'm with kraky and vapo, mostly. However, I do not find runout in excess of .003" on a consistant basis to be acceptable. I have refined my techniques to yield an average of .002", roll a few in the concentricity gauge to check, and forget about it.

In order to achieve this consistancy I outside neck turn once fired brass and use the Lee Collet Neck Sizer. Runout is kept to a bare minimum of less than the .003" and I forget about it.

Runout is EXTREMELY important for accuracy. It should not exceed .002" Stick a crooked round in the chamber, smack it with 55,000# of pressure and expect the bullet to straighten itself out is asking a lot.
Sorry guys, but that bullet will form off center and wobble to the target.

I check runout as well, with the Sinclair gauge. I can get mine under .002. But you know I checked Federal Premium Match stuff for 308, and runout on those were .006 or more...kind of makes you go hmmm...and they shot pretty good to...hmmm. Worth it or not, its just more fun to add to the crazy hobby...

Run out is very important for getting the most accuracy out of your rifle. I performed my own experiments w/ some of my pretty accurate Heavy barreled rifles and found that the groups that had visible wobble (probably .003-.012) the groups would be in the 1-1.5" range but, with the exact same compnents but straight rounds of .001-.002 the groups would be at and below .5" some well below. I experiemented w/ run-out during one spring and found the same results every time. Since then I've tried to get every paper punching round to less than .002 and prferably .001 and all hunting rounds to at least .003 or better.

Run-out does make a difference. It may not be the difference in killing big game at ranges out to 200 yards but, I'm too anal about my rifles and loads and prefer to have every last bit of accuracy I can get.

I straighten my rounds. Usually when loaded from Lee collet dies they seem to be in the .001-.003 range w/ a few being .004 from time to time. I give them a slight push to get them w/in .001-.002. It's very easy to straighten rounds and once you've done a few hundred it's very fast and easy to do. I've probably straightened 1000s this year alone. It's the last step I do in my loading process; from my loading block, to the gauge, straighten, back on the gauge, and into the plastic ammo boxes.

Some think straightening rounds leads to a lose of neck tension and it can if you over correct but when you are just going a few thou it doesn't effect the neck tension a bit.

Good Luck

Reloader

Reloader, what is your process to straighten rounds? just curious...

quote:

Reloader, what is your process to straighten rounds? just curious...

Whiplash,

Anything that will fit over the bullet snugly or fit down over the neck as well. For example another piece of throw away brass, a hole drilled in a hard wood block, a small piece of metal tubing, etc.

I use brass a good bit becuase I've always got a pile of junk brass in the reloading room.

I take a fine point sharpie marker and I roll the round on the gauge until I hit the exact high point, stop it, and place a small mark on the brass at the dial gauge point. Then, I put a slight amount of pressure to straighten. It will take you a while to get the hang of it. Try and not go too far as you will lose neck tension if you go back and forth. After I used this method for a while it's just easy as it can be now. Just apply alittle pressure and stick the round back on the gauge for a second to see how much it moved. Different carts take a diff amount of pressure (For Example: a 300WM is alittle tougher to move than a 22-250 etc.).

This method is easy and it works very well.

Good Luck

Reloader

Thanks Reloader, I think I will have to give that a try that next time I get to the bench, and hopefully add that to my routine...

Something I do to help minimize runout--and I don't use anything but RCBS or Redding standard dies, is to seat the bullet in increments. I start the bullet into the case, then raise the press handle (withdraw cartridge from die), rotate the cartridge 1/4 turn or so, seat the bullet a little deeper, raise the handle, rotate, seat some more, etc. until the bullet is fully seated. This is usually a 3- or 4-step process.

I don't have any scientific or statistical proof of gain, but in my simple mind, if the bullet starts crooked, the process corrects the bad start. I have been successful at working up accuracy loads for lots of customers, getting their rifles to shoot great with hunting bullets. My latest was a M70 with a Douglas stainless barrel that averages .40" for 3-shot groups at 100 yds using Hornady 100-gr Spire Point bullets.

But, as vapodog said earlier--start with a decent barrel and good trigger, get a good bullet/powder combo, and then work on the load. I think that bullet jump is critical, and that is my primary variable I work with. Some rifle/bullet combos like a long jump (.040" or more, and some like no jump at all). Once I establish that distance to the lands, then I will tinker with the charge to get the velocity up around "standard".

And, since I'm being paid to do this, I try to wring all the accuracy out of the round that I can, which includes flashhole and primer pocket uniforming, standard case length, etc. etc.

quote:

Something I do to help minimize runout--and I don't use anything but RCBS or Redding standard dies, is to seat the bullet in increments. I start the bullet into the case, then raise the press handle (withdraw cartridge from die), rotate the cartridge 1/4 turn or so, seat the bullet a little deeper, raise the handle, rotate, seat some more, etc. until the bullet is fully seated. This is usually a 3- or 4-step process.

I agree, I seat my bullets in thirds. Seems to work well.

Reloader

I read somewhere, maybe in a book written by one of the prominent benchrest masters, that for each .001" of runout your cartridges have, you increase group size by .1" Now, I can't verify that as I work exclusively with hunting rifles/calibers, but I suppose one of the world-class benchresters could demonstrate that with their equipment and loads.

quote:

I was considering how much runout I should consider to be tolerable for my hunting rounds

Let's see. A mass produced hunting rifle with a mass produced chamber that will need to fit every brand of that caliber ammo, mass produced cartridges that have to fit every chamber ever made? So basically, the undersized cartridge is laying at the bottom of the oversized chamber. And it's probably sloppy headspace-wise, too. I wouldn't worry about a few thousanths of runout on factory ammo, all things considered.

But correcting those things is why I handload. In my experience, with a Hart barrel and fireformed cases, .005" runout, measured on the ogive of the bullet, is the most I will accept for my hunting ammo in calibers from .257 to .338 in a boltgun. Culling all those rounds with runout greater than .003" does not yield any better field accuracy at the distances I shoot.

I've "tested" bullet runout in 4 different rifles. I'd load say 20 rounds and measure the runout in all of them and pick out the best 5 and the worst 5 and shoot them for groups. In every case the group with the worst runout was about double the size of the best runout groups. I don't see the point in using a good match grade barrel, bed and float, tune or replace a trigger and then shoot crooked ammo. I did get a similar improvement in factory barrels too. I also have tried the seat the bullet in steps, rotating the case each time and have checked the runout and it was no more consistant than just seating the bullet, in fact I created some serious runout in a few rounds by doing this, like .020. Bench rest dies do make a difference, ya gotta have a seating die it might as well be a good one.

The size die and expander causes almost all runout problems by bending the shoulder. Seating almost never does. The problem is over sizing with tight dies and having to force the expander back out.

1. If you roll loaded ammo on a smooth surface you can see the bullet runout if it is very bad. Use that check to verify your dies are working correctly. This works especially well on rounds with long heavy bullets seated well out of the neck.

2. When using a CRF action the feeding of the round jacks the bullet against the chamber to wedge the rim under the extractor. Run your straight rounds through the magazine then check them for run out if you are using a CRF action.

3. Those needle pointed bullets some times touch in the end of the seater screw rather than on the ogive leaving them crooked.

4. Rats.....I will think of the last item about 2 hours after I post this.

quote:

Originally posted by ireload2:
2. When using a CRF action the feeding of the round jacks the bullet against the chamber to wedge the rim under the extractor. Run your straight rounds through the magazine then check them for run out if you are using a CRF action.....

Hey Ireload2, I am impressed. That is the first time I've seen ANYONE mention that (additional) problem with CRF Actions in many many years.

I was going to comment on your #4, but I forgot what you said.

WHAT??? CRF doesn't keep the bullet in line with the bore.....and somehow the guns can still be under moa shooters????
Does this mean the trip down that 24" barrel CAN STRAIGHTEN OUT THE BULLET???

Thanks for your replies. BTW, what is "CRF"?

Make that X2 for me Ireloader2, I have never heard of anyone say that CRF actions introduce bullet runout. I tried what you said in a 358 Win M70 and came up with the same runout that I had before the test, are you trying to say that all CRF actions in any caliber will introduce runout or a specific action caliber combination? Do you have any data to support this?

pearson1662, as for your original post my experience is that the runout is directly related to your accuracy potential all else being equal. Ideally in a perfect world zero runout is what you should strive to achieve, use plenty of lube inside the neck when resizing to keep the runout low and trash any case that has a thick uneven neck or neck turn it to get it back.
bigbull

ps: pearson1662, CRF= Controle Round Feed