30 XCB naked lube vs. PC & lube

waco

waco

Springfield, Oregon
Okay. Frustrating day to say the least. I really hate to make excuses but after over 500 rounds I really think it's time to clean my rifle. That's the only thing I can think of to explain todays mixed results.

This is the exact load I used to shoot sub 2 moa groups on steel at 500 yards. Until today I had not shot these on any target other than 500 yards. I had high hopes.

Bullet alloy. This is an alloy suggested to me by Fiver. 90/6/4 Pb/Sb/Sn water dropped for a bhn of approximately 18
these "naked" bullets were sized to .311" and lubed with 2500+

This same bullet was used to PC. I dumped these into ice water right out of the oven. I check the bhn and they were around 15. I then also lubed these powder coated bullets with the same 2500+ lube.

Everything else was exactly the same. New Starline brass, CCI LRP, 47.5gr H414, and all were loaded to the same COL off of the ogive.

All bullets were sorted to no more than .3gr weight difference. Here is where things get interesting. I used my brothers Magnetospeed chronograph for my numbers.

Bare lubed bullets speeds for 10 shots.
2653
2656
2640
2644
2651
2649
2644
2641
2630
2643
Max 2656
Min 2630
ES 26
Avg 2645
SD 7.42539
Powder coated and lubed bullets. 10 shots
2539
2521
2504
2515
2520
2524
2520
2514
2516
2510
Max 2539
Min 2504
ES 35
Avg 2518
SD 9.3
I got a couple decent groups from both loads and then things went downhill. I was doing my best to keep the barrel cool but groups just kept opening up. Like to 8" groups a 100 yards....:angry::headbang:
Like I said, maybe it's time to scrub the bore. Anyway. here are the better groups of the day for what it's worth.
Note the PC load was on avg. 117fps slower???
Seems odd to me. Your thoughts?
 
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waco

waco

Springfield, Oregon
Guess my pics got cutoff.
In order. Group sizes.
1.58"
2.57"
2.12"
1.71"
 
JWFilips

JWFilips

Well-Known Member
Well waco, somehow I would have expected more from that rifle ( Not you , you are a proven good shooter) Something seems off for both types of lube especially PC! Maybe things get really different then I know about in the +2K world
 
JWFilips

JWFilips

Well-Known Member
I think I remember Ian telling me once that some times it take some distance to stabilize a bullet properly. Maybe this is just that case
 
quicksylver

quicksylver

Well-Known Member
Walter wouldn't any of those groups stand a good chance of hitting a 10 Inch plate at 500yds and wouldn't that be 2moa ?or were you hoping for a 5/8" group at 100yds or am I way off here?
 
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Spindrift

Spindrift

Well-Known Member
A bore scrub is certainly worth a try, something seems to be wrong.
Regarding the lower velocities with PC bullets, my guess is the lower friction is affecting the conditions for powder burn (which are probably marginal in this combo).
 
waco

waco

Springfield, Oregon
quicksylver said:
Walter wouldn't any of those groups stand a good chance of hitting a 10 Inch plate at 500yds and wouldn't that be 2moa ?or were you hoping for a 5/8" group at 100yds or am I way off here?
Click to expand...
Dan. No, I was hoping for 1 1/2" to 1 3/4" at worst I guess. I don't know. Just puzzles me....
 
waco

waco

Springfield, Oregon
Spindrift said:
A bore scrub is certainly worth a try, something seems to be wrong.
Regarding the lower velocities with PC bullets, my guess is the lower friction is affecting the conditions for powder burn (which are probably marginal in this combo).
Click to expand...
Seems possible. I thought the pc loads would be faster.
 
fiver

fiver

Well-Known Member
exactly what I was expecting.
remember when I said how slick they were and not to try an over coat of lube.
now you know why.

your right on that normal 4% figure with the velocity loss too.


I have a feeling that if you used like 7grs of a fast powder you'd also see a similar outcome.
 
Brad

Brad

Benevolent Overlord and site owner
Staff member
I wonder if you are seeing a buildup of lube for the overcoat? Is the carnuba and such leaving a slick yet grabby surface that give start/stop stick that is causing the accuracy issues.

I would be interested to see how the PC shoots, no lube, or powder is increased to get back to the traditional lube velocity.
 
waco

waco

Springfield, Oregon
All I know is that barrel is getting scrubbed down to bare metal before I go back out. I still have some of both loads to try on a different day.
 
Brad

Brad

Benevolent Overlord and site owner
Staff member
I would shoot multiple groups with your normal lube to get a good baseline and see how the barrel handles the fouling over the course of a day.
Clean well and repeat on a different day with the PC to get a fair comparison.
 
Bass Ackward

Bass Ackward

Active Member
Brad said:
I would shoot multiple groups with your normal lube to get a good baseline and see how the barrel handles the fouling over the course of a day.
Clean well and repeat on a different day with the PC to get a fair comparison.
Click to expand...

Barrel’s worn out now. Need a new tube. :)
 
Will

Will

Well-Known Member
Waco your results mirror a lot of mine. To me that’s what has always made shooting cast bullets frustrating. Seems I have a very hard time repeating my results. Even when using bullets from the same casting session.

I’m sure you will get it figured out though. I’m ready for another video of you banging steel at long range with it.
 
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