208 Amax's and tight bores do not mix

bailey1474 · #8 05-01-2007, 03:53 PM

I see. I wish I would have shot them on paper @ 1000 yds. They did yeild several groups under 1.5" @ 400 yds w/some under 1". I think it is a very good bullet. Sure was hard on those milk jugs @ 900+ yds as well!!! Gotta love those polymer tips!!!

BountyHunter · #9 05-02-2007, 06:15 AM

By all indications it is a great bullet and Hornady is taking steps to put out a high quality product. that is why it was a surprise to have one gun shooting in the .5 at 1k and the other 1 MOA. Only difference was bore diameter. Hornady engineers are working with the shooters and testing this themselves to see what is the issue.

Lapping increased the bore diameter and the second gun is not shooting in the .5 range at 1k.

This was confirmed with another tight bore barrel, so the next step is a barrel with the pure .308 land to groove.

Perfect example of why not every bullet shoots in every gun and why a good load for someone might be overpressure or terrible load for the next guy. Someone elses load "indicates" a powder and range of weight charges, bullet, primer combo for you to test only.

BH

BountyHunter · #10 05-02-2007, 06:17 AM

[ QUOTE ]
Lapping increased the bore diameter and the second gun is not shooting in the .5 range at 1k.

[/ QUOTE ]

Dummy, the correct word above is "now" instead of "not". Fingers faster than the brain this morning.

BH

JR · #11 05-03-2007, 12:19 PM

You said they cut an inch off the muzzle and recrowned. Perhaps the initial crown was the culprit? Perhaps there wasn't enough barrel cut in the first place to alleviate the bellmouthing caused by the initial lapping procedure?

JR

BountyHunter · #12 05-03-2007, 01:56 PM

Doubt that was the issue, the barrel was a broughton and they are always lapped with a slight choke at the muzzle with the extra belled part cut off before that.

BH

JR · #13 05-03-2007, 03:37 PM

Well if it was relapped and chopped back before measurement of original, to the crown, any of Broughton's merits had been discarded. Doesn't quite sound like there is enough information there to disregard 'tighter' groove diameters, other than you found when two barrels have been lapped and cut back, they shot better. We're talking .0001" per groove making all the difference..I find it rather hard to swallow..Sounds more like the relapping, and cutting back ended up in a barrel which was a bit more uniform on release of bullet.

JR

JR · #14 05-04-2007, 10:52 AM

Hard to dismiss the results, no doubt, and I'm not trying to argue the fact. I'm arguin, but mostly with myself, hahah, just trying to get my head around it all. While at HS, we shot every rifle for group. I have seen lapping take many a barrel which shot 5/8-3/4" @ 100, to 1/4" and less, but I never figured opening the bore up made the difference. Usually the difference was the bullet was exiting the muzzle more cleanly, as there were so slight of imperfections at the break from muzzle due to dull or misaligned tooling during the crowning process. A guy could 'feel' what was affecting the exit of the bullet, even ever so slight, in the additional lapping session. When the obstruction was cleared, went back downstairs for group, and it performed as it should have.

JR