Is this minutia all for nothing?

[Lofty]

I just got into reloading and Im really getting into the fine details and precision aspect of it all. It appeals to a certain aspect of my OCD.

Anyays, I just picked up a GAP 10 in 6 Creedmoor and was putting some rounds together for it last night. I was checking chambering because the bullet I am using (Berger Hybrids) George says may need feed well.

Its then that I realize how tough a gasser is on ammo. As the BCG slams forward and rams the round into place, I noticed how hard the bullet tip is slamming against the feed ramp. Ive never paid attention before because any precision rifle Ive owned was a bolt gun and on my AR's I didnt care.

So I did a little experiment. I loaded up 10 pieces of brass....basically blanks with no primers and powder. I was super precise with seating depth and concentricity. Then I would pull the bolt back and let it slam forward but I would eject it very slowly to ensure that any change in bullet depth or concentricty was done on the ride forward, since the ride out was irrelevant.

I was a little surprised after rechecking the ammo how much everything has changed. Bullet depth was at least 2-3 thou deeper, sometimes more.....but concentricity was way off. Not surprising considering that the bullet tip is what is guiding the round into the ramp.

So it got me thinking. All the mess and attention to details that reloaders go through to get the most accuracy....does it really matter that much?

I was watching GAPs video of Tyler shooting better than a 1/2 inch group at 1000 yards with the same rifle.

How important can all that be when theres no doubt a gas gun unsettles all the work you do making sure your bullet is perfectly seated but it still shoots lights out?

 

[Graham]

Re: Is this minutia all for nothing?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lofty</div><div class="ubbcode-body">So it got me thinking. All the mess and attention to details that reloaders go through to get the most accuracy....does it really matter that much?</div></div>It matters if you are a Benchrest shooter, cut your own custom chamber dimensions, turn your necks, and reload the same few pieces of brass for the same chamber.

Do the same things matter if you shoot a gas gun that efectively resizes your brass by setting the shoulder back every time the bolt slams shut? Of course not.

And what about other tolerances: Like measuring to less than .1 grain of powder? Have you done any experiments on how much barrel temperature affects velocity within a five or ten round string during a stage?

Practical precision rifle shooting is about paying attention to what matters, and ignoring what doesn't matter.

 

[jcdean]

Re: Is this minutia all for nothing?

Yep, the tip wobbles more than Randy Travis at a traffic stop.

 

[MitchAlsup]

Re: Is this minutia all for nothing?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lofty</div><div class="ubbcode-body">I was watching GAPs video of Tyler shooting better than a 1/2 inch group at 1000 yards with the same rifle. </div></div>

Uh. The workd record for a 5-shot group at 1000 yards is on the order of 1.5 inches (or less than 0.2 MoA) while a 10 shot group is just under 3 inches.

http://mt1000yd.com/1000_YARD_WORLD_RECORDS.html
http://www.bdoutdoors.com/forums/hunting/75975-rifle-shooters-1-000-yard-ibs-world-record.html

 

[Lofty]

Re: Is this minutia all for nothing?

Sorry, I didnt mean .5 inch total, I meant half MOA, I shoulda been more clear on that.

Fast forward to 9:00

Gap-10

 

[MALLARD]

Re: Is this minutia all for nothing?

yes it matters.

determine your distance from the lands, develope a load using that COAL (it should be longer then your magazine) So feed single shot.Push the cartidge into the chamber by hand before dropping the bolt. Fire a group

use the same load but fired from the mag, semi auto.

go see groups downrange...The sinlge shot should be significantly smaller

 

[MALLARD]

Re: Is this minutia all for nothing?

yes it matters.

determine your distance from the lands, develope a load using that COAL (it should be longer then your magazine) So feed single shot.Push the cartidge into the chamber by hand before dropping the bolt. Fire a group

use the same load( bullet brass powder, but adjust COAL and charge weight) but fired from the mag, semi auto.

go see groups downrange...The sinlge shot should be significantly smaller

 

[halon101]

Re: Is this minutia all for nothing?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jcdean</div><div class="ubbcode-body">Yep, the tip wobbles more than Randy Travis at a traffic stop.</div></div>

i dont think thats the tip he is measuring off of.

 

[halon101]

Re: Is this minutia all for nothing?

op - forgive me if you provided the info and i just didnt recieve it, i did read the whole thread.

what kind of crimp if any did you use?

 

[mkollman74]

Re: Is this minutia all for nothing?

Do the least amount you can get away with to obtain the level of accuracy you require. At least that is what I do. I reload so I can shoot, not the other way 'round.

EXAMPLE: For my OBR in .308 I run 44.4 of Varget into LC LR brass and top off with a 175SMK ignited by a FED 210M. I FL size every round every time. I do not weight sort components. I do not uniform primer pockets. I do not turn necks. This produces ~0.5 MOA groups out to 805 yards for me from a bipod/prone. I do ID/OD chamfer after I trim, but I don't need to trim often. If the above was producing marginal accuracy,I would fiddle with variables until I got what I needed.