Loaded ammo bullet runout???

[Trickymissfit]

I honestly think the suppliers of measuring equipment that we rely upon do it as cheaply as they can find away, and quality be damned. Then there is the issue of the reloading equipment itself. They reduce quality to make an even bigger buck. All the while some folks have been running on their name plate for eons; yet their product line is no better than something else comparable for a fraction of the cost. In my book it shouldn't be a crap shoot as to wether or not a press is strait or a die set is on the mark.
gary

 

[Bart B]

Been to a lot of BR matches and even won a few and have never seen a factory rifle win EVER. Either at 100 or a 1K.

Did not know that you shot BR....

Never said a factory rifle did such. I don't shoot BR.
I have no idea how you got such ideas.

 

[boomtube]

"Sierra Bullets uses commercial Redding full length sizing dies on their cases used to test their products for accuracy in SAAMI spec (or virtual copies thereof) chambers. I doubt anyone shoots their bullets more accurate than they do. Sierra doesn't do any case prep whatsoever. And they meter, not weigh, powder charges."

I'm not getting entangled in this but all the above quote 'proves' is that's what Sierra does and that it's plenty good enough for their test purposes, it does NOT prove that their way is the last word on accuracy; YMMV.

 

[Boss Hoss]

Never said a factory rifle did such. I don't shoot BR.
I have no idea how you got such ideas.

Bart--read your last sentence that is where the comment came from. In the BR game .5 MOA will not win anything but a early trip home:


"And it's a myth that cases have to be a "perfect" fit to the chamber with minimum clearance all the way around the case to the chamber for best accuracy. Best proof of this is the M14 and M1 service rifles rebuilt to shoot 7.62 NATO mass produced ammo. With their extra moving parts having to go back into battery exactly the same for each shot, they won't be as accurate as a bolt gun. But they'll shoot a good lot of commercial match ammo under 2/3 MOA at 600 yards all day long; not too shabby at all for new cases, metered charges and bullet runout up to 3 or 4 thousandths. And mil spec chambers, too, which allow for a lot of room around a loaded round. That same ammo in a bolt gun will shoot 1/2 MOA at 600 or better and that's what the benchresters get these days as that's what their rifles 'shoot.

 

[Bart B]

Bart--read your last sentence that is where the comment came from. In the BR game .5 MOA will not win anything but a early trip home

There's been single 5- or 10-shot groups at long range BR matches that have won that match with a .5 MOA group.

And if one gets every aggregate's individual group at 1000 no worse than .5 MOA, they'll set virtually all the agg records.

When I say a rifle shoots .5, or even .75 MOA at any range, that refers to the largest group (or all shots fired) is no larger than that. But I don't think benchresters like to use that terminology or term. They're primarily focused on the smallest group fired. I've asked some long range single group record holders what the largest group their rifle shoots and none will give me an answer; maybe they're too embarassed to do so. Benchresters' smallest groups happen about as often as their largest ones, but I've yet to have any one of them acknowledge that. Out of all shots fired, about half will go into the middle 1/3rd of the distance between the smallest and largest 5-shot group size. One-fourth will go into the upper 1/3rd of that spread and another fourth into the lower 1/3rd. It's those lucky few-shot groups at the small end of that lower third that set the single group records. And the aggregate records are the average size of all groups shot which are typically about 2/3rds the size of the largest group.

There's one 5-shot record group at 1000 yards that was one of several groups fired in a aggregate and the agg group was about 6 inches. That means that some of the groups were bigger than 6 inches. I tried to get him to tell me what his biggest group was but he ignored the question and refused to even discuss it. Looking at all the 1000-yard BR aggregate records is easy to tell what the rifles and their ammos accuracy potential is. Multiply the aggregate group size by 1.5 and that'll be very close to what their average biggest group size is. Therefore, I think I believe no long range benchrest rifle and its ammo shoots no worse than .5 MOA all the time.

 

[Bart B]

"Sierra Bullets uses commercial Redding full length sizing dies on their cases used to test their products for accuracy in SAAMI spec (or virtual copies thereof) chambers. I doubt anyone shoots their bullets more accurate than they do. Sierra doesn't do any case prep whatsoever. And they meter, not weigh, powder charges."

I'm not getting entangled in this but all the above quote 'proves' is that's what Sierra does and that it's plenty good enough for their test purposes, it does NOT prove that their way is the last word on accuracy...

Sierra's tools and techniques do well enough to shoot their best match bullets into .25 MOA at 200 yards, group after group after group....... I don't think anybody else does that well with Sierra's bullets at 200 yards with any other type of tool or technique; if they are, they're not making it public.

And others using the same tools and techniques resizing and preping cases but weighing charges have shot groups equalling current benchrest records at long range; sometimes better. But few want to research this enough to learn its merits. And just as few will ever understand why.

Even the short range benchrest crowd's been moving over to full length sized cases for some years.

 

[Boss Hoss]

There's been single 5- or 10-shot groups at long range BR matches that have won that match with a .5 MOA group.

And if one gets every aggregate's individual group at 1000 no worse than .5 MOA, they'll set virtually all the agg records.

When I say a rifle shoots .5, or even .75 MOA at any range, that refers to the largest group (or all shots fired) is no larger than that. But I don't think benchresters like to use that terminology or term. They're primarily focused on the smallest group fired. I've asked some long range single group record holders what the largest group their rifle shoots and none will give me an answer; maybe they're too embarassed to do so. Benchresters' smallest groups happen about as often as their largest ones, but I've yet to have any one of them acknowledge that. Out of all shots fired, about half will go into the middle 1/3rd of the distance between the smallest and largest 5-shot group size. One-fourth will go into the upper 1/3rd of that spread and another fourth into the lower 1/3rd. It's those lucky few-shot groups at the small end of that lower third that set the single group records. And the aggregate records are the average size of all groups shot which are typically about 2/3rds the size of the largest group.

There's one 5-shot record group at 1000 yards that was one of several groups fired in a aggregate and the agg group was about 6 inches. That means that some of the groups were bigger than 6 inches. I tried to get him to tell me what his biggest group was but he ignored the question and refused to even discuss it. Looking at all the 1000-yard BR aggregate records is easy to tell what the rifles and their ammos accuracy potential is. Multiply the aggregate group size by 1.5 and that'll be very close to what their average biggest group size is. Therefore, I think I believe no long range benchrest rifle and its ammo shoots no worse than .5 MOA all the time.

Bart there is a lot more to shooting at 1k that that let me assure you. I am one of those people who shoot at 1K competitions even won a few have a few HOF points. Not going to get into a ****ing contest here but the manual that was quoted I shoot with one of the guys that wrote that!!!!! He does what I do and more---he spins his with a Junke Machine. I know you mean well and are trying but 95% of the people on this board do not have the equipment or the means to properly test this at 1K.

In IBS BR (read up on the rules) there are group shooters and there are score shooters--I am one of the few in the later because the object is to hit the center of the target. A 6in group is not going to win very often if you are shooting for group at 1K. Maybe when a front blows in during the relay that will happen but in good conditions not likely.

This will be my last post on this subject. When you find someone who knows what they are talking about all of this will become clear as a bell.

 

[Boss Hoss]

"Sierra Bullets uses commercial Redding full length sizing dies on their cases used to test their products for accuracy in SAAMI spec (or virtual copies thereof) chambers. I doubt anyone shoots their bullets more accurate than they do. Sierra doesn't do any case prep whatsoever. And they meter, not weigh, powder charges."

I'm not getting entangled in this but all the above quote 'proves' is that's what Sierra does and that it's plenty good enough for their test purposes, it does NOT prove that their way is the last word on accuracy; YMMV.

Hey "Mr Lapua" are you watching this thread? Why don't you let everyone know why your loading information (old employer) was done that way. If I tell them they will not believe me anyway...

 

[Bart B]

Hey "Mr Lapua" are you watching this thread? Why don't you let everyone know why your loading information (old employer) was done that way. If I tell them they will not believe me anyway...

I'd probably believe you if it was for efficiency and use for different test barrels for the same cartridge. They've been doing it since the 1950's. I learned all about it from their first ballistic tech from a few tours of their Santa Fe Springs plant.

And some folks have been using that same method for decades shooting test groups equalling what the current benchresters do with other tools and techniques these days for accuracy.

 

[RTK]

.

Even the short range benchrest crowd's been moving over to full length sized cases for some years.

What is the reasoning for doing that?? I would think you are creating a less accurate package.

 

[Bart B]

What is the reasoning for doing that?? I would think you are creating a less accurate package.

Check out the section in the following link that starts with: Most top 6PPC competitors run their ammo at pretty high pressures. Such pressures demand that cases be full-length sized each time they are loaded. But the trick is sizing the case just enough to allow proper feeding/extraction and no more.

Speedy's 6PPC -- The Art of Accuracy

It's all based on the fact that chambers or cases (sized or new) are perfectly round. When neck only sized, their body soon starts interfering with the chamber at the body-shoulder junction and the case no longer perfectly centers its shoulder in the chamber shoulder without interference. Bottleneck case bodies need be sized down no more than 1/4 to 1/2 of a percent of their diameters to prevent this interference. They center up front at the shoulcer perfectly when fired regardless of how much clearance there is around them. Measure some chambers and both fired and sized cases from them for roundness and you'll see they're not perfectly round. They're pretty close to within a thousandth or less for chambers and two thousandths for cases. The more uniform case wall thickness is in their body and shoulder area, the more uniformly round they'll be.

One good way to see the difference between fired cases' out of round as well as diameter differences is to drop them into a Wilson case holder used in their trimmers. The holder's reamed to fit the body pretty close, but depending on how a given case is oriented in the holder, it will come to rest at different depths. The smaller diameter ones and those whose out of roundness matches that of the hole in the holder will go in deeper than larger diameter ones and those with mismatched out of round points to the holder. Most folks are surprised in the differences across a batch of fired cases from the same chamber.

 

[Bart B]

What is the reasoning for doing that?? I would think you are creating a less accurate package.

Check out the section starting with Custom Dies Work Best in this site: Speedy's 6PPC -- The Art of Accuracy

The reason they full length resize is to prevent interference between case body and the chamber wall that can cause the front of the case to no longer center perfectly up front at the chamber shoulder when too little clearance happens with neck only sized cases.

Typically, a custom sizing die will reduce the 6 PPC case diameter at the shoulder .00075" to .001". The die will also allow for a little bit of shoulder bump. Redding full bushing dies do this very well for other cartridges, and even as much as a 2 thousandths diameter reduction in fired case body diameter doesn't hurt one bit for 30 caliber cases.

 

[Bart B]

This will be my last post on this subject. When you find someone who knows what they are talking about all of this will become clear as a bell.

Well then, I guess my tests with 15 brand new unprepped cases and 15 once fired neck turned full length sized ones shooting six 5-shot groups at 1000 averaging about 3.5 inch group average with all 30 going under about 5 inches and 3 other 15-shot test groups with full length sized cases averaged 3.6 inches at 1000 proves I don't know what I'm talking about in spite of all the Sierra bullets coming right out of the box, unprepped an stuffed in case necks.

I apologize for ruffling your feathers. I didn't think the realities of what others do to get great and consistant accuracy as what's traditional with benchresters using other tools and techniques. I should have known better to challenge the KIA's with another way to do as well.

 

[Bart B]

Bart there is a lot more to shooting at 1k that that let me assure you. I am one of those people who shoot at 1K competitions even won a few have a few HOF points. Not going to get into a ****ing contest here but the manual that was quoted I shoot with one of the guys that wrote that!!!!! He does what I do and more---he spins his with a Junke Machine. I know you mean well and are trying but 95% of the people on this board do not have the equipment or the means to properly test this at 1K.

In IBS BR (read up on the rules) there are group shooters and there are score shooters--I am one of the few in the later because the object is to hit the center of the target. A 6in group is not going to win very often if you are shooting for group at 1K. Maybe when a front blows in during the relay that will happen but in good conditions not likely.

This will be my last post on this subject. When you find someone who knows what they are talking about all of this will become clear as a bell.

Sorry you misinterpret what I've posted.

You've not the wherewithall to understand what I've said. I thought you did.