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Can primers reduce E.S.?

 
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  #8  
Old 11-07-2013, 08:33 PM
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Re: Can primers reduce E.S.?

More and more this is starting to sound like black magic.
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  #9  
Old 11-07-2013, 11:55 PM
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Re: Can primers reduce E.S.?

Yes, different primer can change ES.

It's not black magic just physics, chemistry and engineering with to many permutations to empirically prove them all.
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  #10  
Old 11-08-2013, 08:21 AM
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Re: Can primers reduce E.S.?

Quote:
Originally Posted by Canadian Bushman View Post
Could you help me understand different striking adjustments? Im afraid im completely unaware i could be making adjustments.
Primer striking is affected by a bunch of things. And even while striking is sufficient/reliable to set off every primer, it can still kill grouping if at a bad setting.

Does it makes sense that primer striking would affect grouping? Not to me..
But I found that it does and I suspect optimum is not the same for every primer brand.

The pin itself(it's boltface protrusion) should be adjustable inside your bolt. This is an easy adjustment to striking. If you change triggers, take care to measure pin protrusion beforehand, especially if you've already invested in load development. With this you can reset it if performance falls apart.
With a different trigger the firing pin can pull back a bit more or less, there might be more/less drag on release. Ever notice drag at the action tang? Or bolt handle bump/turn on dry firing?
Pay attention to this stuff.
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  #11  
Old 11-08-2013, 08:51 AM
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Re: Can primers reduce E.S.?

A good example of the differences in primers is almost any cartridge based on the 6mm BR case(Dasher, BRX, BRDX etc).

Loaders have found that the CCI 450 IS THE GO TO primer bar none for low ES, SD and accuracy.

Actual pressure tests have shown that changing primers can result in a 7K PSI change.

German Salazar on the Rifleman Blog is one of the few that has done actual pressure tests with strain gauges on testing primer pressure variances.

Also, primers have different characteristics on cup hardness and power levels that do not make them unilaterally interchangeable with every load.

That is also why Qload and other supposed super programs that claim to tell you everything beforehand are not accurate and reliable It is easy to take the data and reconfigure the program to replicate it, but hard to do up front and be really accurate.

Many of the more knowledgable smiths tailor firing pin hole size to firing pin diameter to avoid high pressure issues with cratering back into the firing pin hole. That is why you will often see bolts with firing pin holes that have been bushed to a smaller size. They also tune the springs and pin for no contact/drag within the bolt body.
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  #12  
Old 11-08-2013, 09:06 AM
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Re: Can primers reduce E.S.?

There is so much more to a primer than i ever stopped to consider.
So could a wallowed out firing pin hole also be a detriment to accuracy?
Is there a set a procedures that i could follow to help me tune a load to a primer efficiently, or is it just sort of a hit or miss scenario?
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  #13  
Old 11-08-2013, 02:34 PM
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Re: Can primers reduce E.S.?

Canadian Bushman
Changing primers can skyrocket your pressures!!! The NRA has recorded changes as high as 13,000psi. Pistol ammo is the worst. But the dynamics going on in the cartridge case of the shot are very complex and beyond us mere mortals to predict. That being said, some guide lines from the experts:

1) Different primers can and do change the load.

2) Changing from a magnum primer to a regular primer of the same BRAND and TYPE will lead to lower pressure most of the time and the same pressure some of the time.

3) Changing from a regular to a magnum primer of the same BRAND and TYPE will RAISE PRESSURE! This is a done deal. It always goes up.

4) Different Brands have different characteristics. Different amounts of initiators and fuel. So it stands to reason there would be a change in load performance. Example; I have a load for 30/06- 180gr Seirra SpBT+ 56.5gr IMR4350+ Rem 9 1/2 LRM primer+ WW case. SD= <20fps. Change the primer to Federal #210, a primer that has always delivered VERY low SD, and this load goes to 30fps SD. Alot? No. But without trying you won't know. Why? Don't have a clue.

5) IN MY EXPERIENCE, the standard LR primers give similar pressure and velocity across the brands. But you will find a specific load likes a certain primer. There is a HUGE difference in Magnum LR primers. Federal is King of the Hill, the Remington #9 1/2 is pretty close. Both of these are pretty hot numbers. All the rest fall into the last category of hotter-but-not-by-much. Some don't show much difference than standard LR primers but I do not use any of them as the Federal & Remington #'s suit my needs.

Hope this helps. The Match versions are held to closer manufacturing tolerances and I feel they are worth it for everything but practice (cheaper) loads. No performance difference but somebody is checking everything twice or thrice and you are less likely to have a bad (out of spec) one.
Hope this helps. Change your powder around first in a new load then try different primers to dial it in. Primers are the next to the last thing I play with. Seating depth is the final resolution.
Just sayin'.
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  #14  
Old 11-08-2013, 03:05 PM
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Re: Can primers reduce E.S.?

Canadian Bushman
I forgot to mention in my last post that I have found Winchester standard LR primers seem to be hotter than the other Brands. If you start with the Winchester you can switch to the others without a problem if the load isn't on the edge. If you develop a load for the other brands back off maybe 0.2gr if you go to the WW standard LR.

I prefer Federals for most of my loads but that is in rifles. CCI's are my favorite in pistols for no particular reason. CCI #550 are better SPM than the others but that's my experience.

Primers are like car brands, some like Chevys, some like Fords. I buy them all because I'm not getting caught short again. When the last drought hit I found my Small Pistol supply was less than I thought (< 2K). I like to keep a wide selection in the Large Rifle size because in rifle loads brand seem to make a difference for some loads and switching types (regular vs. magnum) helps when the powder charge is 60grs or more and ball powder seems to need the hotter spark plugs too.

Just keep shooting and you will find trends in your efforts too. Just remember to keep good records. I didn't at first (41 yrs ago) and some of my best loads are lost to me now.
Maybe if I check in the pyramid in the back yard.......
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