Lowering ES via primers-test

[savagedasher]

As long as we have gravity it's the main one . Larry

 

[lawrence97]

I tested some S&B's out of my 284 shehane at 1000 to see if they were worth using for local matches and they do good compared to my br2's using the same load. The ES and SD was lower compared to the br2's but I don't pay much attention to the numbers if paper tells me otherwise! I will continue to test and see if they are worthy of going to bigger matches.

 

[dbramley]

Till you get low ES I don't think you can not have vertical at distance . Math should tell you that . Larry

I just read an interesting article on "positive compensation". Basically states that if you are in the middle of the node bullets of differing velocities exit the barrel at a time such that the bullet is cast into the group as a result of the location of the muzzle at the time of bullet exit. I suspect there is way too much "math" involving barrel harmonics to say simply that a lower velocity round is going to impact lower.

 

[rardoin]

As long as we have gravity it's the main one . Larry

True...IF...IF...we are shooting mortars!

 

[dkhunt14]

Till you get low ES I don't think you can not have vertical at distance . Math should tell you that . Larry

I have a load in my 338 Lapua IMP that varies a full grain of powder and 50 feet per second with 300 grain Bergers and it still shoots same point of impact at 1000 yards. So that statement is not always true. In fact I have seen almost the same thing with the Dasher and 105 grain bullets. The target tells the story and it doesn't lie. Matt

 

[savageshooter86]

Only have experience with my 308 FTR. Load hammers with extremely low ES.

Just had me thinking because this load isn't shooting well and has high ES

 

[Jay Christopherson]

Only have experience with my 308 FTR. Load hammers with extremely low ES.

Just had me thinking because this load isn't shooting well and has high ES

I think if that were my target, I'd start working with your Wolf primers to nail down your load and put the others back on the shelf.

 

[mikecr]

I was forced into some testing stemming from opened grouping from usual.
Turned out that my firing pin had slipped a bit under it's set-screw. All primers were firing just fine, but groups had opened.
Anyway, once discovered I was in a bad position because I did not know where the pin should be set(there was no indent or mark on the pin). So I spent a day at the range running a full spread test with varying pin protrusion settings from the bolt face.
I saw grouping open and close and open just like seating nodes. The gun already shot well, but when I found the best, it bought me another 1/8moa better than I had ever achieved with the gun, so this effort ended up well worth it.

Important is that every primer fired just fine, all the way through this testing.
And it makes me wonder if the abstract in 'choosing a primer' could be influenced by chosen seating standard and striking from the system. I've yet to test it (a lot of work), but someday I intend to explore this with a handful of different brands -each optimized as far as striking (per the target).

 

[memilanuk]

Very interesting! I know of people (@Jay Christopherson for one) that have had known-good guns/loads go in the toilet when the firing pin tension got too low; replacing it with a new one 'fixed' the problem. Seems to be somewhat less of a problem with factory actions (over sprung to begin with, from what I gather). But what you're describing does raise a curious question of whether a given primer, that normally *doesn't* shoot well in a particular gun, could be induced to work better by fiddling with the firing pin / spring. Not sure it would be my first choice, but still intriguing...

 

[DocDoc]

@milanuk

I don't do anything out of the ordinary, just polish up the carbon with a stiff nylon brush. I don't notice anything weird on the seater, besides what you would expect, resistance goes up as interference goes up. You have to realize, the bullets I was running at 5+ thousands have extraordinarily large and distinctive pressure rings. Enough so as when they pass through the neck, it doesn't spring back enough to put a lot of grip on the shank. So 5+ on a normal bullet would likely produce much higher resistance, since it is gripping more length. Here's one below, it looks like a healthy girl in yoga tights!

View attachment 1003392

Tom

Looks like the start of the boat tail is about half way up the neck? Is that right?