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Zee
Senior MemberPosts: 27,466 Senior Member
Uniforming Primer Pockes - Why?
Zee
Senior MemberPosts: 27,466 Senior Member
Why am I doing this?
This question popped in my head just now as I was uniforming primer pockets of some factory brass I just shot today. As I sat there doing so, I thought........."Why the Hell am I doing this?" I just shot a .162" three shot group with this factory loaded brass this morning.
Looking over several of the groups I've shot with this factory ammo in the past, it seems that if I do my part.........this brass in factory loaded form will produce regular groups in the .1s".
So, I'm asking an honest question. Why..........after the brass is once fired..........am I then taking that brass and uniforming the primer pockets? Seriously, I would like clarification as I've been doing this step for years now. And, I JUST came to the point of.......WHY?
Am I improving the brass that much? I can't shoot .1" groups at will in either pre-uniformed or post uniformed. But, they are regular enough with both to make me wonder if that step is the reason or that I just get things right on occasion and other times......I don't.
I'd REALLY like to start skipping this step. But, I'll continue if there is a legit reason. I just think I finally woke up, though. Am I REALLY good enough a shooter to tell the difference? If the brass groups well either way, then it's more on me than the extra step of uniforming the pockets. If that's the case............screw uniforming them!!!!!
Help!!! Suggections? Recommendations? I come groveling to those that got me started in reloading in the first place.
This question popped in my head just now as I was uniforming primer pockets of some factory brass I just shot today. As I sat there doing so, I thought........."Why the Hell am I doing this?" I just shot a .162" three shot group with this factory loaded brass this morning.
Looking over several of the groups I've shot with this factory ammo in the past, it seems that if I do my part.........this brass in factory loaded form will produce regular groups in the .1s".
So, I'm asking an honest question. Why..........after the brass is once fired..........am I then taking that brass and uniforming the primer pockets? Seriously, I would like clarification as I've been doing this step for years now. And, I JUST came to the point of.......WHY?
Am I improving the brass that much? I can't shoot .1" groups at will in either pre-uniformed or post uniformed. But, they are regular enough with both to make me wonder if that step is the reason or that I just get things right on occasion and other times......I don't.
I'd REALLY like to start skipping this step. But, I'll continue if there is a legit reason. I just think I finally woke up, though. Am I REALLY good enough a shooter to tell the difference? If the brass groups well either way, then it's more on me than the extra step of uniforming the pockets. If that's the case............screw uniforming them!!!!!
Help!!! Suggections? Recommendations? I come groveling to those that got me started in reloading in the first place.
"To Hell with efficiency, it's performance we want!" - Elmer Keith
Replies
Hey, I did this step because I was told to do so by YOU knuckleheads. Now I'm wondering...........why?
Hey! I resemble that remark!
I am not as good a shot as you are Zee, and my rifles are not nearly as tuned. I am still pretty much a rookie rifle reloader, but it seems to me the more uniform your pressure vessel is the more uniform your pressure curve will be.
I did something fun today. I wrinkled a case while loading my .243's so I pulled the bullet and powder and had this primer in a bad case just waiting to be popped. I put on my safety glasses and hearing protection, clamped the case in the vice, got out a nail and a hammer detonated that Winchester large rifle primer. It was pretty vigorous! I also lit off some spilled H4350 ( about 10 gr ) just to see it burn. It was a great reminder visually of what is going on inside the casing.
Ignition from the primer is not gentle. It is forced through the primer pocket hole into the powder, and when the powder is stacked up it essentially burns one spot. That ignition point has to expand into the rest of the powder and if it isn't uniform I can see it igniting differently, either a hotter spot or a less hot spot in the powder.
Also powder does not "explode" unless under pressure, it just burns. In my mind a uniform hole / pocket for the ignition to go through provides a more consistent start to the reaction.
So I am a very anal reloader, trying to get everything as close to the same as possible. I don't know what I am going to do if I ever get a Hornady OAL length gauges for my 30-06, .308, .243, and .223. I am even considering chamber casting to know my best OAL's.
D
Alcohol, Tobacco, Firearms and Explosives.... now who's bringing the hot wings? :jester:
All of what you said seems to deal more with the flash hole than the primer pocket.
I am meticulous in other areas of loading. But, I don't weigh brass, primers, bullets to sort by weight but, still get ammo that is better than me on a drop of the hat basis. I'm just beginning to think that uniforming the pockets ain't making enough difference either.
Do you see a difference?
Honestly, I am not good enough to see a difference. I suppose I try everything possible to eliminate any variable except for me and the gun. Then I know the gun's potential.
D
Alcohol, Tobacco, Firearms and Explosives.... now who's bringing the hot wings? :jester:
― Douglas Adams
JAY
Words of wisdom from Big Chief: Flush twice, it's a long way to the Mess Hall
I'd rather have my sister work in a whorehouse than own another Taurus!
In theory, more uniform depth gets you more uniform lock time from primer strike to primer pop. I wonder if anyone ever actually computed the nanoseconds that would amount to. . .
We went through a very intense period of pocket uniforming, neck turning, and sorting cases by weight. Three things changed this: #1, we woke up one morning and suddenly realized that we were shooting NRA Highpower, deer rifles, and the early games that lead to F-class - - NOT Benchrest; #2, the brass industry in general got a whole lot better, and we realized that after our time prepping cases was factored in, it was cheaper to buy Lapua and Norma brass than to fritter away our lives tuning a lesser product; and #3,we came up with the loading process that I've outlined elsewhere that works to minimize the effect of internal variables.
So, we've basically got the process down to where getting jacketed to shoot under 1.5 MOA is usually pretty easy, getting under a 1-MOA is no huge challenge, and squeezing 3/4 MOA out of the dedicated target guns doesn't burst any blood vessels. Sometimes we get luckier at that level of effort. Anything more than that would start to require going back to the crazy-anal measures that began to suck all the joy out of the game.
I've said it elsewhere and I'll say it again here - KEEP IT REAL! If you are already creating ammo that can reliably shoot groups inside a deer's eye socket from 300 yards, what functionally is to be gained by trying to improve it?
"Nothing is safe from stupid." - Zee
I just don't feel like uniforming the pocket anymore. That is the one step that takes the fun out of handloading. The one step I hate.
But, regardless the brand, I don't think I'll do it to any of the new brass I use either. Whether Winchester or Remington.
Just kinda burned out on that step, I guess.
What could you be shooting at that requires better than .1 to .2 MOA precision? Seriously, I have never shot a group with a center fire that was less than .5 MOA.
D
Alcohol, Tobacco, Firearms and Explosives.... now who's bringing the hot wings? :jester:
Personal desire. No other reason.
Pitch that Lead Sled and do your rifles a favor-- you are embarrassing them...
http://www.midwayusa.com/product/412484/caldwell-rock-front-shooting-rest
I have one.
I prefer the Lead Sled mostly because I am too tall for the benches at the range. If they built them up another foot I could use them, but at "standard height" I have to contort into yoga poses to get in line with the scope. Most of the time I have to kneel, instead of sit to get low enough to shoot the rifles when they are rested.
D
Alcohol, Tobacco, Firearms and Explosives.... now who's bringing the hot wings? :jester:
Actually, smokeless powder should never explode, especially under pressure since we make use of it under usually extreme pressures, that is if your definition of explode is what mine is. At work we considered an explosion as a Detonation or a rapidly accelerating Deflagration. A detonation doesn't turn corners and will blow out adjacent walls. It generates destructively high pressures.
A detonation is where you have a flame front at or above the speed of sound. A deflagration is where the flame front is below the speed of sound. This is considered a burn not an explosion. And even under pressure, and especially under pressure it is still a burn. Burns or slower flame fronts generally generate usable pressure levels, whereas explosions create destructive pressure waves.
For instance in and automotive or truck engine. If your gasoline engine is pinging (Sometimes called detonation or pre-detonation) it usually needs a higher octane or rather slower burning fuel(This is providing your timing isn't too far advanced or you don't have some other problems. This pertains in general if everything else is up to spec.). The fuel in the cylinder is detonating as the pressure increases. This can cause damage to your engine and is usually occuring before the piston reaches Top Dead Center.
The reason why you have slow burning and fast burning powders is because different calibers and cartridges need different powders with different burn rates. The slower burners generally work better in long barrels and over bore cartridges. The fast burners normally work better in larger diameter barrels with a more generous expansion ratio. You get a more usable pressure curve and more shove on the bullet with the correct powder in a given rifle. Note that this is a very simplified explanation. In reality things are a little more complicated, so unless you are a certified ballistician, take my advice and don't try and reinvent the wheel, just do like most of us and go by a book on listed powders for specific loads in specific cartridges. You might live longer like that.
OK Thread highjack over, back on subject:
Now as for primer pocket uniforming. Does it help? I'm not entirely sure but suspect it is probably one of those deals where shooting a more normal average rifle you will never see the difference or at least not enough difference to make it worth while. However, if you're into serious competition shooting a really potentially accurate rifle, it might make a difference where hundredths or thousandths of inches might make the difference in a winning group and an also ran.
Bye the way, I do it anyway, just because I can, LOL!
Son that's somebody with nothing to do with his time but keep me in trouble with mom.
Once you do, I bet you will be surprised.
At our range we have concrete benches that just don't move. But they are reasonably high enough for most anybody to line up on the scope especially since the stools are adjustable for height. So far, Wheelsman is the only forum member to go there with me, but I think he was impressed. But we had the assistance of a real bench rest shooter to help design them. They are right at 30 years old but still work great
Son that's somebody with nothing to do with his time but keep me in trouble with mom.
That...and a lot of folks get what they settle for.... I like to wring every bit of accuracy I can get out of my rifles....it's one of those things that floats my boat...
I do know my F Class friends, some of whom have won National Championships, they just buy Lapua small primer brass, then load and shoot the stuff.
The only time “reaming” is of any importance would be with semi automatic mechanisms. It would be a safety concern if a shallow primer pocket allowed a high primer. According to CCI in the article, Mysteries And Misconceptions Of The All-Important Primer http://www.shootingtimes.com/ammo/ammunition_st_mamotaip_200909/ several conditions have to be met for a primer to ignite. It turns out high primers are the most common cause of mis fires. If the anvil is dangling in the air, or the primer cake is not wedged between the anvil and the primer cup, the primer will mis fire. You read posts on this all the time, the reloader did not seat the primer deep enough. However, if you stick spacers in your primer pockets, or, you have shallow primer pockets, then you have the potential for a fully seated anvil and a high primer. Then in an automatic gun mechanism, you could have a slamfire just due to the bolt face hitting the high primer. So, reaming pockets to depth for ammunition used in semi autos is a reasonable measure.
http://sharpshootershootingbenches.com/
Son that's somebody with nothing to do with his time but keep me in trouble with mom.