Inthebeech
New Member
Background:
With either my Lyman 358311 (165 gr RN) or Lyman 358212 (148 gr RN), I get boringly repeatable 2 ¼ inch groups at 50 yards out of my Model 14, needing only to push these bullets at 720 f/s.
Objective:
Find an accurate, fifty yard load with a bullet that cuts clean holes using a Smith and Wesson model 14.
Set Up/Process:
Ransom rest mounted identically for all sessions. One range session per velocity. Three different velocities total. Two representative DEWC bullets (so six days all of which were identical regarding weather); benchmark velocity that I use with my accurate RN load (720 f/s), an intermediate (840 f/s) and a third (950 f/s). One group is six rounds (one cylinder). Note: The highest velocity matches the spin rate (36,000 rpm) of the 14 inch twist Cold OMM/Python travelling at the same speed as my accuracy load (720 f/s). Starting from a cleaned gun and using my standard RN load, shoot enough "settling in" groups to confirm the gun is settled in the rest and also shooting the typical 2 ¼ - 2 ½ inch group. This required 2-3 total cylinders (2-3 groups). Look down the barrel without touching the gun to verify no leading.
Same press, same dies, same brass (Remington match), primers. Note: To get to the third and highest velocity I needed to switch from BE to WST.
Test:
With two DEWC's of identical diameter and hardness, I loaded these bullets up to increasing speeds until I achieved a similar spin rate compared to 720 f/s out of a 14 inch twist. Out of my 18 ¾ twist Smith, this would be about 950 f/s. Shoot 3-5 groups of six for each velocity and each bullet. The two wadcutters are the Magnus #501 (same hardness and diameter as my RN load but unknown lube) and my Hensley & Gibbs #50 (same hardness, diameter and lube as my RN load). Three different velocities, two similar DEWC bullets.
Results:
No difference between the two DEWC bullets. Starting out at 720 f/s, groups were around 12 inches in diameter. The intermediate load gave groups that fell to about 6-7 inches. Groups from the 950 f/s load were 5-6 inches in diameter.
Notes:
Clearly, I'm not going to get there with a solid DEWC at reasonable velocities and if this is representative of what a ballistics engineer would predict, then a solid DEWC cannot give an accurate, 50 yard group out of the 18 ¾ twist. Does this suggest that, since this is the same spin rate as one would get from a 14 twist at target velocities that the solid DEWC was NOT used by PPC shooters for their fifty yard stage? Maybe they only ever used HBWC's?
How different would a HBWC perform; not because of the "expansion of skirt diameter" theory, but because it is perhaps more stable?
I haven't any SWC design molds so I don't know for sure but perhaps this design gives the required accuracy with cleaner looking holes?
Through measurements of case ID's, OD's, bullets, loaded rounds, I can say that the case always expands the full amount of interference. The bullet does not swage down when seated. I used match brass which has a .010 wall and no internal taper for the full length of a DEWC. This might not be the same for standard brass which has a taper and about a .011 wall thickness at the mouth).
Have I done enough to confirm the statement that target velocities will, under no circumstances, permit an accurate, fifty-yard group out of an 18 ¾ inch twist (six inch) barrel when using solid, full wadcutters?
With either my Lyman 358311 (165 gr RN) or Lyman 358212 (148 gr RN), I get boringly repeatable 2 ¼ inch groups at 50 yards out of my Model 14, needing only to push these bullets at 720 f/s.
Objective:
Find an accurate, fifty yard load with a bullet that cuts clean holes using a Smith and Wesson model 14.
Set Up/Process:
Ransom rest mounted identically for all sessions. One range session per velocity. Three different velocities total. Two representative DEWC bullets (so six days all of which were identical regarding weather); benchmark velocity that I use with my accurate RN load (720 f/s), an intermediate (840 f/s) and a third (950 f/s). One group is six rounds (one cylinder). Note: The highest velocity matches the spin rate (36,000 rpm) of the 14 inch twist Cold OMM/Python travelling at the same speed as my accuracy load (720 f/s). Starting from a cleaned gun and using my standard RN load, shoot enough "settling in" groups to confirm the gun is settled in the rest and also shooting the typical 2 ¼ - 2 ½ inch group. This required 2-3 total cylinders (2-3 groups). Look down the barrel without touching the gun to verify no leading.
Same press, same dies, same brass (Remington match), primers. Note: To get to the third and highest velocity I needed to switch from BE to WST.
Test:
With two DEWC's of identical diameter and hardness, I loaded these bullets up to increasing speeds until I achieved a similar spin rate compared to 720 f/s out of a 14 inch twist. Out of my 18 ¾ twist Smith, this would be about 950 f/s. Shoot 3-5 groups of six for each velocity and each bullet. The two wadcutters are the Magnus #501 (same hardness and diameter as my RN load but unknown lube) and my Hensley & Gibbs #50 (same hardness, diameter and lube as my RN load). Three different velocities, two similar DEWC bullets.
Results:
No difference between the two DEWC bullets. Starting out at 720 f/s, groups were around 12 inches in diameter. The intermediate load gave groups that fell to about 6-7 inches. Groups from the 950 f/s load were 5-6 inches in diameter.
Notes:
Clearly, I'm not going to get there with a solid DEWC at reasonable velocities and if this is representative of what a ballistics engineer would predict, then a solid DEWC cannot give an accurate, 50 yard group out of the 18 ¾ twist. Does this suggest that, since this is the same spin rate as one would get from a 14 twist at target velocities that the solid DEWC was NOT used by PPC shooters for their fifty yard stage? Maybe they only ever used HBWC's?
How different would a HBWC perform; not because of the "expansion of skirt diameter" theory, but because it is perhaps more stable?
I haven't any SWC design molds so I don't know for sure but perhaps this design gives the required accuracy with cleaner looking holes?
Through measurements of case ID's, OD's, bullets, loaded rounds, I can say that the case always expands the full amount of interference. The bullet does not swage down when seated. I used match brass which has a .010 wall and no internal taper for the full length of a DEWC. This might not be the same for standard brass which has a taper and about a .011 wall thickness at the mouth).
Have I done enough to confirm the statement that target velocities will, under no circumstances, permit an accurate, fifty-yard group out of an 18 ¾ inch twist (six inch) barrel when using solid, full wadcutters?
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