"What is the top velocity for GG boolits with good accuracy and no leading"

[303Guy]

The title says it all! Over on Smokeless Paper Patching we have been talking about what can be achieved with GG and it seems like pretty fantastic! A number of us are interested in what you GG folks are doing with your rifles. Loads, accuracy and velocity and of course what guns and twist rate would be very interesting to us all. Looking forward to hearing from y'all.

[BruceB]

MY standard hunting load for the .416 Rigby represents about the fastest normal-use cast load that I'm shooting these days. The velocity is 2050 fps (365-grain RCBS) and the accuracy is great....right around one inch for TEN-shot groups from 100 yards.

Development is just beginning in search of a reliable .303 British recipe at about the same speed. I want to take a pair of .303s hunting in northern Alberta next November, and I'd be a happy hunter if my NOE 316299s at 204 grains with soft-points would group that well at 2100 fps.

I haven't tried for maximum speed, since the above performance meets my needs very nicely. 2000-plus fps will give good trajectories to 200 yards, and that's all I ask for hunting.

[303Guy]

...right around one inch for TEN-shot groups from 100 yards.

Holy Cow! That would equate to a one hole three shot group! Wow!



All the best with you 303 quest. I'm sure you will get it right. May I ask you to keep us posted?

[BruceB]

Yep, my #1 in .416 is a shooter, and no mistake,

On one range excursion, I had the .416 and a Whitworth .223 (the "Mini Mauser") along.

I fired the .223 with a variety of loads first, without any fantastic results. Of course, this is a seven-pound sporter and squirmy on the benchrest, but I recall that the best result was about 1.25" for ten rounds.

Switching to the .416, it proceeded to deliver a ten-round one-hole group of just under one inch...TIGHTER than the .223! (I measure such groups by taking the largest dimension of the raggedy hole and subtracting one bullet-diameter from that measurement.)

I will say that the "characters" of the rifles were rather different.....365 grains at 2050 is a wee bit more energetic than 55 at 3100!

[nanuk]

I was wondering who would step up and start the thread.

Good going 303Guy!

I too look forward to the flood of info we are surely to receive!

[nanuk]

BruceB 365 at 2050 is greater velocity/energy than my old 500BPE, or the 50 sharps cartridges in BP.

enough to take anything in NE.

and that is a WEE BIT Energetic!

[Bret4207]

Whats a "GG"???

[btroj]

Grease groove is all I can think of Bret. Must be a term developed by someone who had his patch wrapped a bit tight.

[Bullshop]

Yes GG = grease groove. Someone on a discussion about paper patch mentioned that he went to PP because he read in a 1970s vintage Lyman cast boolit book that 1800 fps was the limit for GG with good accuracy and no leading.
I posted that the membership at castboolits has raised that bar buy a good margin.
Now I think they want to know if I am goofy or if they may find some collaboration to my statement.
My own personal experiance put my practical limit in most cases at between 2400 and 2500 fps. Not that I get leading beyond that but find that is most often where accuracy drops off.
I know I have read of others going beyond 2500 fps so hope others will jump in and share what they have. My loading notes contain lots of data in several calibers with pet loads in the 2400 fps area. Many of these loads have been successfully employed in the game fields.

[geargnasher]

Dan, that's my experience a well. I have achieved as much as consistent, repeatable 10-shot, 2moa groups at 100 with .30-'06 in the 2700 fps arena, but it was a LOT of work, and had a narrow ambient temperature window.

Most 30-caliber stuff I've tried gets peak accuracy between 2200 and 2350 fps, but that's in typical ten-twist bolt rifles like the Model 70 and Savage.

Gear

[runfiverun]

i have an old thread around here showing sub 1/2" groups at 2700+ with my 223.
the velocity isn't the hard part maintaining accuracy is the trick.
i have gone in the 2700 fps range with an 0-6 but the accuracy was not there unless you need a 10" group at 100 yds.
this is probably gonna start the arguement again but the twist rate of a bbl helps maintain accuracy with velocity.
you can overcome the faster twist rates with some loading tricks and such, but most off the shelf designs and heavier weight boolits most often used just won't do it.
that may be just why i recently bought a 14 twist 30 cal bbl.

[Bullshop]

I get good accuracy in 375 cal shooting our 375gn boolit from the H&H case with a 1/12" twist at 2400 fps. Same design from a 375/06 with 1/12" twist tops out at 2200 fps with excellent accuracy.
Same boolit design at 275gn but in 35 cal does equally well in a 1/14" twist 35 Whelen at very close to 2400 fps.
I am not sure what twist remington uses for thier 416 mag but we have come to expect equal performance with our NEI mold for a 400gn DD GC also at 2400 fps.
Just a few examples that come to mind.

[Von Gruff]

I have my 7x57 and 404J both in excess of 2400fps getting 1 1/2 in 100 yd hunting accuracy.

Von Gruff.

[303Guy]

So, is it easier to get top velocity and accuracy from the bigger case volume cartridges and similarly bigger calibers? I'm pretty much limited to my collection of 303 Brits. The one I have in mind has the original full length barrel and I favour the heavier boolits. The chamber will accept 245gr cast but the magazine will only accept 208 grainers and those are both grooveless. 208gr at 2200fps is quite do-able with the Brit but not sure about accuracy at those levels. Does one have to use gas checks at those velocities? Any idea how a 'frosted' bore would handle cast boolits at those velocities? (I have two of those). Perhaps I could go to an even slower powder than AR2209/H4350 and fill the case? (The 208gr smooth side is my boolit of choice).

[waksupi]

I'm shooting my .358 at 2180 fps, 290 gr. boolet. That is beyond any factory specs.
In .308, 2450 fps with a 170 gr.
.223, 2680, don't recall boolet weight.
Very good accuracy with all, no leading.

[Bullshop]

303Guy
Its all about pressure/time. When you look for an appropriate powder for a certain application look for the one that gives the highest velocity at the lowest pressure.
That usually means slow powder.
The fact that your 303 has a long barrel will be very helpful getting the most from slow powders.
As I understand the 303 only works at pressures in the low 40s. That is magnum handgun pressure level so not a difficult range to work in at all for top velocity your cartridge is capable of. In other words its much like the 30/30 in that its not at all hard to duplicate factory ammo ballistics with cast.
A frosted bore is still very capable of shooting well it may just need cleaned more often.

[runfiverun]

im fairly sure you got a 10 twist in the 303.
i'd look for about 1900 fps. to start
a gas check is very helpfull, and any other base protection you care to try will help increase the velocity.
i know you have worked with a few of those. [bran]
now you know you need to engrave the rifling and keep the boolit from skidding.
you [i'm assuming] are gonna use these for hunting and a 200 gr will do the job easily, but you need both hardness and flexibility here.
waterdropping a low antimonial alloy will help in this regard.
you can add grease grooves to that boolit with a canellure tool, or use your waxy lube it seemed to work well before.

[303Guy]

Aah yes, I had forgotten about knurling. Without knurling the lube tended to get knocked off and that was without magazine feeding. Mmm .... a wheat bran wad in place of a gas check! That would make the powder I have about ideal - it leaves a small air-gap. Thanks for that. I actually want this more for target shooting. Paper patching is way too difficult for any kind of volume loading - as fun as it may be (I'm busy patching up boolits for my Pig Gun as I speak and I count them like the fingers on my hands! ) I would like, if possible, to use the same alloy for hunting and target, patched and unpatched.

[runfiverun]

ppatch for hunting.
waterdrop for target.
that may keep things close enough for sight settings.
and get you easier trigger time.
the filler making up the difference in lower powder volumn for target work.
anyways you are gonna have to try a few different things to get that boolit to work both ways.

[Jack Stanley]

The number one mark three I bought years ago seemed to like the LBT two hundred fifteen grain slug I used in it . I normally don't use fillers for any reason but in this particular loading I needed some pressure . I was using one of the discontinued Reloder powders from Hercules . I was chronographing loads and watching accuracy at the same time .

Accuracy was OK up to about just over eighteen hundred , as the charge was increased the soot on the cases decreased and accuracy increased . All this was fine untill the accuracy went out the window . Since the powder was most of the way up the shoulder of the case I decided to go off the reservation a little . I backed off the charge and got one of the LEE dippers that would dump enough attrition milled corn cob to a third of the way up the neck . That way the bullet compressed everything and hopefully I'd still be wearing my fingers .

Right away I had good accuracy and less soot on the case and the pressure didn't seem bad at all . So I started increasing the charge a little at a time untill somewhere just over two thousand feet per second groups opened up . looking over my targets I looked like a velocity of 1950 feet per second might work so I tried charges near that again . Sure enough , no leading , great accuracy , cases looked like factory pressures and an average velocity of 1960 feet per second .

I used up the seven or so pounds I had of it and wished I had more but discontinued meant just that . I don't know what the energy was but I thought it to be similar to the old mark one black powder load and cleaner to boot . All this is a good reason to keep your old loading notes I guess huh?

Jack