Possibly runout of the bullet itself? As mentioned, solid copper won't obturate like lead.
Possibly runout of the bullet itself? As mentioned, solid copper won't obturate like lead.
Taking a break from social media.
I'm pondering the crimp angle myself, trying to figure out a way to quantify it. I see no Profile Crimp or collet type crimpers, only taper crimp. Case neck tension?
I'm rambling now.
Malo periculosam, libertatem quam quietam servitutem
I prefer the tumult of liberty to the quiet of servitude
-Thomas Jefferson
I prefer dangerous freedom over peaceful slavery.
Originally Posted by BN
There may be something to this angle, combined with diameters of the bullet itself.
Is the powder recent production, fresh, or old stuff?
How close are you to the chronograph? I've noticed that with real "blasty" rounds like, 10mm and.38 Super, I need to back up a little more to get consistent results.
We could isolate Russia totally from the world and maybe they could apply for membership after 2000 years.
An observation from my side.
In a lot of cases like these the bullet comes under fire. Mostly the person/s has never used solid copper or brass bullets and blame the bullet for the problems that do arise.
They don't realise that they are using mixed, 5 to 30 times reloaded, brass that has been dodgily processed and works OKish in their range loads only because lead cores are forgiving and hides sloppy loading practices. Brass are culled as needed: cracks, bulges, torn rims, etc.
I don't know blue bullets, but I assume it is a lead core powder coated bullet. Slightly oversize to ensure good grip and seal in the barrel. Process brass, flare it, seat it, don't crimp. Voila, quick and easy.
When loading the solid copper or brass bullets:
Do you remove burrs on the case mouth?
Do you flare to ensure that you don't cut off some of the (to size) bullet diameter?
Do you seat and crimp your bullet in such a manner that the bullet will not have setback?
If you crimp, are you deforming the bullet with your crimp process?
How old is your barrel? A worn or rough barrel will have a negative effect on muzzle velocity. Lead core bullets will again be more forgiving.
What is the diameter of the barrel? Some barrels are oversized and lead core bullets are more forgiving.
And also, how does the bullet over or under perform with a 40 or so fps spread?
Sent from my BV8900 using Tapatalk
@JCL can probably address all these excellent points better than I can. My attempts are inline below...
JCl and I have observed similar low 'outlier' velocities, but I'm using 800X and Cutting Edge while he's using Power Pistol and Lehigh. My pow is fresh, and I'm pretty sure his is as well. But the other data we have eliminate powder as the culprit: velocities using coated or jacketed lead bullets have extreme spreads below 10fps, and no obvious low velocity 'outliers'.
Measuring the bullets is in my to-do list. Thanks for that suggestion.
Good question. I usually put the chrono ~8-10' away. This seems to work because we measured consistent velocities for equivalent or even heavier loads using other bullets.
All good questions. Thanks for the suggestions. I'm using once-fired Starline brass. There's no shaving of the bullets on seating. I use a Lee Factory Crimp die, and the spring collet makes deforming a bullet difficult. However, the FCD will swage an oversized bullet. But, loaded uncrimped rounds don't look unusual. Measuring the bullets will help eliminate this possibility.
My barrel is a stock G20.4 barrel with around 2000 rounds.
Do you mean over or underperform in accuracy? Hard to say at this point because I'm just shooting through the chrono at an 8" plate at 25-30yds. There isn't any obvious change in POI.
“There is no growth in the comfort zone.”--Jocko Willink
"You can never have too many knives." --Joe Ambercrombie
TLDR: The only variable separating the consistent velocities (155 & 200 gr. XTPs and 200 gr. Blue Bullets) and the inconsistent results from the copper solids is the projectiles themselves. Charges were individually weighed in all instances.
"The older I get, the more I think that just staying home and drinking the good stuff by yourself is way underrated as a healthy practice." - Totem Polar
"An entire worldview devoted to being offside." - feudist
Have you guys mic'd the diameters and lengths as yet? Groove width and depths as well?
Another question. Have you taken the exact cases that the copper/brass bullets were loaded in and loaded the blue bullets in them and checked velocity and accuracy? A small test that I've seen showed a variance of up to 40fps just with different flash hole diameters.
After seating and crimping, what is the variance on the case mouth?
Have you pulled loaded bullets and compared to new, unloaded bullets?
Also, what is your average sample quantities when calculating the deviation ( Not sure if I read that info or not ) ?
And lastly for now, I don't think 40 fps is extreme when you compare it to a lot of factory loads.
Sent from my BV8900 using Tapatalk
Great questions @Kriek. I’ll be getting back to this project in a couple weeks.
“There is no growth in the comfort zone.”--Jocko Willink
"You can never have too many knives." --Joe Ambercrombie
How consistent is the diameter of the copper bullets?
Have you measured your bore?
Copper and brass are much less ductile than most lead alloys, and even small variations can have a much larger effect since they don't obturate as easily.
Reply With Quote