Varget in the .30-30 ?

[w30wcf]

Geoff,

Wow! Your rifle's bore/groove dimensions are larger than normal. I have a Marlin 336A made in '78 with micro-groove rifling and it has .301" bore and a .308" groove diameters.

Based on the shallow grooves in your rifle, I am wondering if it is an older marlin.
When micro-groove rifling was introduced in 1955, the factory specs called for .304" bore and .308"groove diameters. Yours is larger but the .004" difference is close to being the same.

Several years ago I had some experience with 2 different marlins of early vintage. Both had barrels close to the Marlin 1955 specifications. The bullet I chose to test was Lyman's 311041. Bullets were made from Linotype and lubed with NRA 50/50 lube. Bore riding diameter was .301" which was .003" smaller than the bore. Driving band diameter was .310".

The initial test load was 36 grs. of H414 giving 2,000 f.p.s. Both rifles shot this load well and averaged slightly over 2" @ 100 yards for 5 shot groups (Both rifles had receiver sights.)

However, when I switched the RCBS 150 gr. bullet (Linotype .302"/.310") and pushed it to 2,300 f.p.s., groups expanded to 5+". The "small for the bore" nose diameter was not supporting the forward portion of the bullet causing groups to really open up at the higher velocity. By comparison, the RCBS bullet shoots just fine in my 336A (.301"/.308") at 2,300 f.p.s.

What diameters are the bore riding / groove diameter portions of your bullet?

Perhaps a .311" diameter jacketed bullet (.303 British) would give you an accuracy benchmark to compare to and to try and exceed(?).

Sincerely,
w30wcf

[grumpy one]

First, my Marlin's serial number is 19058*** (which means it was made in 1981), and stamped into the action in the bottom of the hammer recess there is an 8. I traded it for a .303 Martini about 8 years ago, and it seemed to be almost unfired - everything tight and covered with burrs and sharp edges in the feed system. It has a half-cock system, it does not have a trigger lock or a rebounding hammer. The trigger is gold coloured, I think made from aluminium.

It is interesting that you referred to two of your development bullets being made from linotype. You have mentioned a number of loads that seemed to me to be above the point where I have lost accuracy, apparently due to excessive pressure on the bullet. My alloy is water-dropped 3% tin, 5% antimony. In my first days with cast bullets I was using pure foundry type, which is ultra-hard, but I was undersizing it and developed nasty leading problems (foundry type turns out to be very difficult to remove from barrels, unless you cheat and shoot it out). One of the issues I hope to resolve is whether I am going to need to use very hard bullets if I am going to use the heavy loads you and Felix have both mentioned. Since I have nearly 300 pounds of foundry type already smelted and stored under the bench, there is no difficulty in switching to bullets way over 30 BHN at the drop of a hat. Air cooled foundry type runs to 33 BHN, I don't know how hard it would be water-dropped but I'm guessing it would be pretty hard. A 50-50 foundry type-WW alloy is in effect linotype with a couple of percent of extra tin. Incidentally pure foundry type is about as brittle as glass.

I am using 50/50 Alox/beeswax lube, bought through ebay from somebody called Jake. I have 20 sticks in stock, so I don't expect to run out any time soon.

The GC bullet I'm using is Lee C308-170-F, lapped to give an as-cast driving band diameter of 0.313, and a nose diameter of 0.307. It is about 0.002 oval, and those are the minimum dimensions, at right angles to the joint line, so maximum dimensions are 0.315 and 0.309. I size to 0.312 - I've dabbled with 0.313, but until I get the groups tighter I won't be able to detect any difference there may be. When I chamber and extract a round, the rifling has engraved the nose parallel to the joint line but has not touched at right angles to the joint line. I lapped the driving bands before I lapped the nose, so I could watch for effects of the nose fitting alone. So far I haven't been able to see any effects from nose fitting. I've only ever made one test with 311291, with a 0.300 nose, and it wasn't very good (1.3" at 55 yards, using 18 gr. 4759), but unfortunately I'm experiencing variability of group size that extends up at least that far.

[w30wcf]

Geoff,

1981.....hmmmm.....where were the Marlin quality control inspectors when your barrel was made?

With your modifications, it sounds like bullets made from your mold fit the barrel ok. I would suggest making some linotype equivalent alloy and giving that a try.

If you don't already do so, pre seat the gas checks to make sure they are completely flush onto the bullet base before lubing / sizing. For best results, I would also suggest orientating the bullets when both sizing and loading them into your rifle.

For initial tests use only bullets that weigh within .3 grains (heaviest - .3 grains)

Hopefully your results will be closer to what you would wish to obtain from your rifle.

Good luck,
w30wcf

[Chuck 100 yd]

I went up to the gun club yesterday with 50 rounds (.30-30) loaded with Lyman 311041 cast of WW + 2% tin GC ,air cooled. Loads were all Varget and WLR primed. I started at 25gr. and worked up in 1 gr. steps. firing 5 shot groups at 50yd.
I got velocity variations in the 80`s and 90`s untill I got to 28 gr. and then with 29gr. it just started to settle down with Velocity spreads of about 60fps and SD in the 20`s. This load is about 1925 fps and at the top end of my bullets strength.
I dont want to drive a fairly soft hunting bullet at 2000 fps and lead the bore just to be able to use Varget.
I have had great results with Varget in the .308 Win. at 2000 fps + using lino and 50/50 lube but I think that I will try another powder for the .30-30 with WW GC bullets for hunting.
I did get 1" 5 shot groups at 50yd.with 28gr, but virtical stringing seems the norm due to wide velocity changes with all other loads of Varget.
I will be trying 4895 and 3031 next using the same bullet. More later.

[Bass Ackward]

I went up to the gun club yesterday with 50 rounds (.30-30) loaded with Lyman 311041 cast of WW + 2% tin GC ,air cooled. Loads were all Varget and WLR primed. I started at 25gr. and worked up in 1 gr. steps. firing 5 shot groups at 50yd.
I got velocity variations in the 80`s and 90`s untill I got to 28 gr. and then with 29gr. it just started to settle down with Velocity spreads of about 60fps and SD in the 20`s. This load is about 1925 fps and at the top end of my bullets strength.
I dont want to drive a fairly soft hunting bullet at 2000 fps and lead the bore just to be able to use Varget.
I have had great results with Varget in the .308 Win. at 2000 fps + using lino and 50/50 lube but I think that I will try another powder for the .30-30 with WW GC bullets for hunting.
I did get 1" 5 shot groups at 50yd.with 28gr, but virtical stringing seems the norm due to wide velocity changes with all other loads of Varget.
I will be trying 4895 and 3031 next using the same bullet. More later.

Chuck,

Very mythodical. I would have changed to a magnum pistol primer. I prefer WLP. That's all I use in the 06 size cases once I go above 70% case capacity fill. Will cut your wide swings and allow you to launch a soft bullet even faster.

Just so you know.

[Chuck 100 yd]

Thanks BASS A , I will give them a try, Must have a thousand or so for my various pistol caliber levers laying around.

[grumpy one]

Geoff,

1981.....hmmmm.....where were the Marlin quality control inspectors when your barrel was made?

With your modifications, it sounds like bullets made from your mold fit the barrel ok. I would suggest making some linotype equivalent alloy and giving that a try.

If you don't already do so, pre seat the gas checks to make sure they are completely flush onto the bullet base before lubing / sizing. For best results, I would also suggest orientating the bullets when both sizing and loading them into your rifle.

For initial tests use only bullets that weigh within .3 grains (heaviest - .3 grains)

Hopefully your results will be closer to what you would wish to obtain from your rifle.

Good luck,
w30wcf

Sorry I've been missing for a while - had problems getting into the site, which the Gunload Master kindly fixed as soon as I let him know.

I haven't wasted all of the intervening time - I bought a Lee hardness tester and tested a bunch of my cast bullets, with results that were startling (to me at least). All of my gas check bullets are water dropped. I tested 59 of my 311291, and found a mean hardness of 18.5 BHN, with a standard deviation of 2.5, a minimum of 14.3 and a maximum of 24.8. Air cooled 311255 cast from the same alloy gave mean of 14.3, standard deviation of zero, minimum of 14.3, maximum of 14.3. Yep, my water-dropped bullets varied all the way down to identical to air-cooled. I tested 13 of my C308-170-F (same alloy, water dropped) and got a mean of 19.1, standard deviation of 2.9, minimum of 14.3, maximum of 24.8. Seems like I'm a really lousy water-dropper, and I might as well face facts and stop doing it. I have some 311291 made from air cooled lino on hand (mean hardness 19.6, standard deviation 0.7, minimum 19.3, maximum 20.9) which I can try in the 30-06 (they are only .311 across the driving bands as-cast, so they won't fit the 30-30). I can cast some C308-170-F made from lino, as you suggest, and I'll brew up something along the lines of 2% tin, 8% antimony as a slightly softer alternative.

I have no data on what effect those wild variations in bullet hardness have had, but at the moment I'm hoping this will turn out to have been a major contributor both to my variability of group size and to the problems I've had getting any reasonable group size with the stiffer loads you and Felix have mentioned. The odd bullet with a hardness of 14.3 BHN mixed in with a group shot with 34 grains of W748 in a 30-30 probably wouldn't do much for group size. Even my "accuracy" load of 18 grains of SR4759 (which lists at 33,000 psi) might be a bit of a challenge to those soft bullets.


Geoff