Just me being me

[Harter66]

I'm an aircraft mechanic (A&P) by 1st trade ,I just jump into projects that seem major to some and seem to border on mundane to me. An engineer once said to me "A bumble bee is not only physically ,but mechanically unable to fly , aparently nobody told the bumble bee " .

Shortly after I cast and shot my 1st sucessful little bitty group from my grandfathers S&W 38 special I leaped into rifle boolits . Soon I hope the scars will fade some . That was not my hour to be sure ,I had tumbling ,leading so bad that the 2 rifles looked like smooth bores ,hours spent unleading, wornout brushes , bent cleaning rods , oh and I was slightly frustraighted with the casting process as well. Thank God I finally found this place and all of the skilled,not always patient,knowledgable folks here.

The next flash of brillance suggested that if a solid copper/gilding metal bullet with shank grooves looked like a sleak fast pointy boolit that there should be a mould to make 1 . No such luck ,but I could spend the big bucks , draw some things up and maybe I'd luck out. Not really what I had in mind.

Enter the bumble bee ! Aka the sleak pointy cast boolit with a plain base no less . My boolit is 1.21"long
.314 base
.312 middle land
.310 forward land
.295x.07 grooves (dia.x width)
.302 bore ride
.09 nose flat
16" radis ogive
.4 shank length (base to forward land edge)
.4 nose ride length
.4ish ogive
200 grns from WW
When I plugged it into am online BC calculater it gave me .476.


On Friday morning I shot my "308-200" in my 30-06' with its 1-8.5 twist in to 4 pretty little 5 shot groups of 2" and under. They were loaded into Winchester WW brass with CCI lg rifle primers and Red Dot at 10,10.5,11.0 grns. They flew through the chrony at 1250,1300,1350 round numbers. The 10.5 1300fps load showed a high low deviation of just 14 fps.

How do I get zero lead in the throat plus 4" and zero lead at the muzzle minus 4" with a lube star on the crown ,but have about 2" in the middle of the bbl w lead? Could that be where the pressure peaked out ,14-16"from the bolt face ?

[Buckshot]

..........A 30-'06 with a 8.5" twist? Who made the rifle or barrel? Have you shot cast out of this rifle before now? What lube did you use? How did the loads group, range? Filler, card wad?

..................Buckshot

[lwknight]

Lead in the middle!! I would hazard a guess that your lube is playing out about the middle and the pressure is getting high enough to make the boolit obturaate the barrel at that point.
Or, your powder is also fizzing out about where the lube is playing out.
I would add more antimony to make the boolit cast slightly larger and be harder too.
It could go either way. Just a hazarded guess.

[Wayne Smith]

With a lube star on the muzzle lube isn't fizzling out in the middle. Something else is going on. I'm wondering about the barrel, who made it, etc. Might there be a slight increase in diameter there that allows a little gas cutting and then tightens down? I don't know if this explains the phenomon, but it's the closest I can come off the top of my head.

[44man]

That could be it, would not take much, not enough to even feel.
But something just hit me, could that distance be the vibration node for the barrel?
None of us knows what the vibration does to cast. This would make an interesting experiment with one of those rubber dampers put at that spot.

[excavman]

Red Dot is a fast/hot powder. It may be melting your plain base boolit just enough by mid-barrel to leave deposits behind. Try a slower powder say Unique or 2400.

Larry

[Harter66]

Buckshot,
The bbl is as far as I know 1965 factory on this Savage 110LH . No wads or filler. Most of my rifle casting "fun" in the op happened in this rifle. It does shoot the LEE 309-160 ok as well. My lube is 1 1/8 lb candle wax 14 oz Vaseline and 2 tbls+ STP, Barry Darrs more or less.

[Harter66]

Buckshot,
The bbl is as far as I know the 1965 factory bbl on this Savage 110LH. No wads or fillers. These were 50 yard groups with the smallest being 1.8x1:9. The largest being 1.5x2.5. Most of the agivation described in the OP was in this rifle. My lube is basically Barry Darrs wth a little more wax.

[Harter66]

Knight ,
The muzzle slugs 300/308 I needed the 314 at the base for the throat. That seems like a lot of boolit already. I'm using water dropped WW. The leading was more like stripping really than melt and fuse.

[Harter66]

44 ,
Bbl hum ,pressure, velocity ,all peaking at once possible not a thought that occured at all.

Wayne
If a prior owner had shot all heavies I could have a swollen bore that would not be visible. The twist certainly suggests that it was special ordered for heavies.

Excaveman
This rifle seems to prefer at this point the faster powder. Unique has given me some issues I this rifle with other boolits.

[wiljen]

Savage 110 was a 1:10 twist as far as the savage record books are concerned. Unless it was a special order item, even in 1965, they were 1 in 10.

I'd slug it from the muzzle and see if the slug slides more easily through that leaded spot. If it is a slight increase in barrel diameter or even a tool mark at that point, you should feel it.

[Archey]

Harter, so glad to hear that I am not the only A&P on here. I am currently working for a repair station primarily on large helicopters. What about you?

[Harter66]

Archy,
I got mine via apprenticeship. I've worked on everything from J-3&4 Cubs to a P-51D and so many V-tails I can't count them all. A Free Lance now days had a shop for a while. I have just a couple of clients now , I like it better this way. I'm on an Army ammo depot for wages these days .

[excavman]

I flew into Hawthorne from Columbia, CA a couple times to go gamblin', nice little town. I am a CFI and was an airport manager for a while, had a maintainence shop but never finished my A&P.

Larry

[Wayne Smith]

Harder, have you shot that same load but with a hard wad? If it is gas cutting a wad may stop it. If it is a rough place in the barrel, as you suggested in your description of the leading, it won't.

[44man]

Limb Saver and SVL both sell a barrel de-resonator. I see one in Cabela's. I don't shoot a rifle much but have to wonder if it could cure something like this.
When I shoot my BPCR I have to rest the barrel at the node point when I use sticks.
I retired from United after 42 years, ramp and fueler but I hung out with all the A&P's. Many come to hunt and shoot. One of my best friends got laid off, went to PIT to work at a small airport and just got laid off again. He is moving to VA to work on Blackhawk choppers.
They gave him several rides, what a rush that must be! :drinks:

[Harter66]

Wow sooo many wing nuts who'd of thought it.

I'm thinking back the load down now to maybe 10.8 and try it

I'll look for a limb saver next time I get to Reno or Carson

As I write this , it occured to me would stock tip pressure change this if it is a bbl hum thing . I'm full floated from the bbl nut out. Maybe I should try that. I could use the forward sling stud for screw presure , it is bushed from the inside and through threaded. Just as a test. Thoughts, anyone tried this?I read about it someplace.

[405]

Harter66,
Zone of leading?? hmm, could be a lot of things. None certain. My thought is that it is residual colloidal lead particles in the powder gas plasma getting layed down in that zone. I've seen it happen with copper jacketed bullets at regular, high pressure smokeless-- where somewhere in the bore a zone of copper fouling is deposited. I think Krieger barrels website has a write up on that theory. Could easily happen the same way with cast lead. The pressure curve of red dot is going to be pretty short, sharp and peaked toward the front end of the burn cycle. Don't know if that peak would be at 16" inches or not, my gut tells me the pressure peak with that load would be well before the 16"- but that's just a hunch.... my gut is hungry right now and it could be sending false signals. :)

[SharpsShooter]

With a lube star on the muzzle lube isn't fizzling out in the middle. Something else is going on. I'm wondering about the barrel, who made it, etc. Might there be a slight increase in diameter there that allows a little gas cutting and then tightens down? I don't know if this explains the phenomon, but it's the closest I can come off the top of my head.

My first thoughts also. Did you slug the bore full length?

SS

[44man]

Wow sooo many wing nuts who'd of thought it.

I'm thinking back the load down now to maybe 10.8 and try it

I'll look for a limb saver next time I get to Reno or Carson

As I write this , it occured to me would stock tip pressure change this if it is a bbl hum thing . I'm full floated from the bbl nut out. Maybe I should try that. I could use the forward sling stud for screw presure , it is bushed from the inside and through threaded. Just as a test. Thoughts, anyone tried this?I read about it someplace.
It might and is worth a try. None of us knows what is going on in the barrel so any of your experiments will not go to waste. I look forward to what you find.

[abunaitoo]

I've always wondered, what does A&P stand for?????

[44man]

I've always wondered, what does A&P stand for?????
Airframe and powerplant.

[Harter66]

I went and shot some more today trying some Unique @ 8,9,10,11,12grs . I am resigned to the bbl being ............ umm .......... swollen as opposed to bulged.
The groups were at 50 yards and were consistant @ 1.25-2.25 inches , some fool left the Chrony switch on last so no velocities .
An odd thing happened though the last group @ 12grs shot about 2" low at its center compared to the other 4 groups.

[405]

Don't know about the barrel swell or bulge being the culprit in laying down a zone of lead? Still could be lead abrasion or erosion at ignition or shortly after. Starting in the case neck, case mouth, chamber throat or leade... then depositing at some point down the bore.

As far as a lower POI with a faster (higher pressure) load that is common to see at shorter ranges. Even more so with handgun length barrels. With higher velocity the bullet is out or the bore before muzzle angle of departure has increased to max due to recoil.

[JKH]

Here are some pics from Harter66


http://farm5.static.flickr.com/4072/4636532878_e02102aaf4_b.jpg

http://farm4.static.flickr.com/3349/4635926185_6da7aed743_b.jpg



Okay, here thy are, sorry for the screwup! [smilie=1:

[Harter66]

Thanks Jeff.

In the pics you can see the bullet that got me driven to shoot a pointy cast boolit it is on the rightb it is a 20mm. The boolit to the far left is from the donor mould the 309-160 LEE my 308_200 in the middle. The other is the 50 yard 5 shot group 12 grs of Unique.

[Harter66]

More info to add to this . It seems as if there is a quite tight place in the bbl just before the leading starts, in fact it is right at the rear sight dovetail and seems to be "choked" around the mill work for the front sight as well. The muzzle end appears to be down to .300 in the grooves.

Could that be safely lapped out or am I best served to rebbl?

[Wayne Smith]

Sounds like you found the problem, or at least a problem. Yes, it can be lapped out. If you want to do it very well run a rod into the barrel with a plug on the breech end the diameter of the lands. Pour in a slug of lead and let it harden. You have made a lap that perfectly fits your barrel. You can pull the slug part way out, oil it and put some grit on it and lap that tight point. If you lap it from the breech you can create a barrel with a very slight choke from breach to muzzle at the same time you smooth the barrel. It will take several different slugs as you work, and a lot of time. It will be worth it.

Or you can shoot some lapping boolits through it. This makes it smooth and the same diameter all the way from one way to the other.