308 issue

[Harter66]

So I have the 172 gr 301618 . I've shot it with some success in a couple of 06's without too much fooling around but in this particular 308 it just doesn't seem to be offering any hints of which way to go. I have run a few hard and a few soft,dry patched unsized and "ironed on" with no joy or even a hint that it might have liked something. I haven't wet wrapped any yet so that is still on the list.
What's weird is that ammo wise this is the 1 rifle that just doesn't care about what goes down the bore from hand assembled pull downs to interloks to factory core locks and 70s Argentine surplus. It even went along with all but max loads and unchecked "all the 30 cal moulds" . I've been up and down the ladders with 3031 (it's all but gone),H4831 and IMR 4350. I've posted Chrony speeds that are close ,not 5 fps but strings of 5 under 30 fps and still can't get 3 on a 16"square at 50 yds .

I've run 2 laps of green bar and the same with 2 reciept papers. This Savage allows me to wrap over the ogive and seat as shallow as the bottom band and still eject the round intact at 310 it needs to have just more than a flat flair to keep the bullet in place at 311 it requires a firm hand but without the over center flair slips out at 312 it will stay put but is pullable with some force by hand in unsized cases. Each step being easily removed assembled. I haven't shot enough cast to remember with certainty but 312 seems like the cast that sealed up and shot well. At 301 I get all 6 lands marking the naked core from breach to muzzle . The bore is 308 x 301 +.000 -.0005 as my tools only allow for an eyeball 4th place. The 301 die from Buckshot just polishes the as cast boolits starting with the middle of the top band so I tried some as cast also . I'm beginning to think this maybe 1 of those fabled pieces that won't shoot patched boolits.

[CJR]

Harter66,

I would suspect you have three (3) problems;

1. Your dry-patching does not have enough shrinkage force to hold the PP on the PPCB. Try wet PP.
2. 308W have an SAAMI chamber entrance diameter spec of 0.310"D. The chamber's 0.310"D entrance diameter is most likely shearing off a part/side of the PP circumference, of your 0311"D PPCB, before it reaches the bore. Then the PP completely slips off the CB in the bore. The PPCB must reach the bore before the PP is sheared by the grooves on its journey to the muzzle. During a proper journey to the muzzle, the PP remains between the CB and the bore's groove diameter but the PP is sheared off by the tops of the barrel grooves. On muzzle exit, the high RPM spins the groove-cut PP off while the bare CB continues to the target. Therefore as the NRA found, by testing, the wet-patched PPCB final diameter should be 0.308"D to prevent early paper shearing by the chamber's entrance diameter.
3. The NRA Cast Bullet Manual recommended only W760 powder for their 160gr. 301618 PPCB. This progressive powder starts accelerating a PPCB slower, with lower maximum pressure, but with a higher average pressure for a higher muzzle velocity.

Hope this helps.

Best regards,

CJR

[62chevy]

I want to Paper Patch my .308 too but need more info so subbing this tread to see results.

[Harter66]

I'm afraid that this may be a very delayed project.

I will wet wrap a few tonight if I can get a little wiggle room . I have had mixed results but more success with dry wraps in several rifles ,I simply didn't consider it for this 1. I also didn't try this without or with a minimum tail.

[62chevy]

I'm afraid that this may be a very delayed project.

No problems I get update to my email.