Ladder rounds

[archeryrob]

I created a ladder round project to throw 30-06, 175 grain, gas check, powder coated, spire tipped bullets with 4198 in .5 grain increments from 2100 to 2650 FPS. So far I've shot over the 2400 mark and the rounds all cluster good, the only change is high power chargers creep higher up the scope. So I have 4 round of each charge and maybe 18 ladder steps. I want to see how fast i can shoot with cast and no lead or fouling at all. Patch the barrel and it's hardly even dirty.

I went trough 11 steps the other day and the first 4 in order were fine and the last of the 4 off as the barrel got hot. Let the barrel cool a long while and it keep heating up faster. Hotter chargers and into the afternoon it seemed t take forever to cool the gun back down. I almost resorted to running the truck air conditioner and standing it to have vent blow on it.

First question - Is there any way to keep the rifle barrel cool shooting this much? I spend more time doing nothing waiting for it to cool.

Second - Is there some way to tell what ladder step is best? Fastest without grouping breaking down or some other sign? I do not have a chronograph, just using GRT assumed speeds from calced loads.

 

[Varminterror]

First question - Is there any way to keep the rifle barrel cool shooting this much? I spend more time doing nothing waiting for it to cool.

You can use a barrel cooler, but really, cooling time is cooling time.

Minimizing how many rounds you expend during load development testing is another viable option - same amount of time, just less temp because you're not cooking as much powder through the rifle.

Second - Is there some way to tell what ladder step is best? Fastest without grouping breaking down or some other sign? I do not have a chronograph, just using GRT assumed speeds from calced loads.

Yes. Creighton Audette Ladder, Dan Newberry OCW Test, or Satterlee/Audette velocity curve. Without a chronograph, the Satterlee/Audette test is out, and the Audette Ladder and OCW Test are really the same thing, so the real decision you have to make is whether you want to mark bullets to identify your holes or just shoot at different aiming points. Easy peasy, lizard squeezy.

 

[AJC1]

I like light charges in the summer for exactly that reason. 4198 is a great powder for doing that. I like blue dot in 30-30 for the same reason. Unless you have terminal energy requirements, the lowest node you can find is the winner for cast in my book. I haven't has as good of luck with powders faster than blue dot but 2400 and 4227 are big fun and low barrel heat because the charge is so small. Quite a few people like red dot for the application.

 

[JFrank]

I created a ladder round project to throw 30-06, 175 grain, gas check, powder coated, spire tipped bullets with 4198 in .5 grain increments from 2100 to 2650 FPS. So far I've shot over the 2400 mark and the rounds all cluster good, the only change is high power chargers creep higher up the scope. So I have 4 round of each charge and maybe 18 ladder steps. I want to see how fast i can shoot with cast and no lead or fouling at all. Patch the barrel and it's hardly even dirty.

I went trough 11 steps the other day and the first 4 in order were fine and the last of the 4 off as the barrel got hot. Let the barrel cool a long while and it keep heating up faster. Hotter chargers and into the afternoon it seemed t take forever to cool the gun back down. I almost resorted to running the truck air conditioner and standing it to have vent blow on it.

First question - Is there any way to keep the rifle barrel cool shooting this much? I spend more time doing nothing waiting for it to cool.

Second - Is there some way to tell what ladder step is best? Fastest without grouping breaking down or some other sign? I do not have a chronograph, just using GRT assumed speeds from calced loads.

You don’t need a chronograph, shoot less rounds to help with heat, I use a table fan & mirage shield on the barrel, color the bullet tips and shoot at one point of aim from the greater distance your comfortable with to get bullet separation on paper.
When judging we look for the overlapping rounds while increasing in powder charge.

 

[KYregular]

I find to keep the barrel cool between rounds I pull the bolt and let as much air get thru it while I ponder lifes unanswered questions or check my brass during cool off. love the 30-06, really don't have to let it cool as long as say, a 300 win or weatherby.

 

[King Medallion]

I shoot something else while the 1st cools off. I usually have 4 guns with me to test, and after each load is fired, clean the bore of each. By the time all 4 are fired and cleaned, new targets put up, barrels are cold and ready for the next test load to be fired.

 

[JFrank]

I shoot something else while the 1st cools off. I usually have 4 guns with me to test, and after each load is fired, clean the bore of each. By the time all 4 are fired and cleaned, new targets put up, barrels are cold and ready for the next test load to be fired.

How in the world can you get any consistency cleaning so much ?

 

[denton]

Compressed air though the barrel will cool it quickly.

 

[King Medallion]

How in the world can you get any consistency cleaning so much ?

Cleaning in between each test load? Is that not what your supposed to do? Each test load with a fresh cool bore. whats wrong with that?

 

[JFrank]

Cleaning in between each test load? Is that not what your supposed to do? Each test load with a fresh cool bore. whats wrong with that?

Nothing wrong if the conditions don’t change but they’re only clean for one round and clean barrels have more friction and typically that makes rounds hit low or off center until carbon builds a bit, count how many rounds it takes to stabilize then run whatever test against a clean bore each round test.

 

[Varminterror]

Cleaning in between each test load? Is that not what you’re supposed to do? Each test load with a fresh cool bore. whats wrong with that?

No, cleaning between each test load is NOT what should be done for centerfire. Starting each load with a “fresh bore” is introducing inconsistency, OR you’re stuck shooting a lot of extra rounds to no benefit to re-foul the barrel over and over.

 

[King Medallion]

ok, thank you for that information

 

[archeryrob]

Thanks I have not been back out to finish it. Too much to do or too much rain when I have time to fit in a field to shoot. The ladder steps all group about the same and only difference is as i go up the ladder in grains the groups creep up the target in the scope. When I get impatient the 4th round can drift if I try repeating ladder steps too fast.

If faster rounds are grouping is not the fastest ladder step that groups good the best load?

I have a separate target printed for each ladder step with 4 holes in it and date, bullet weight and assumed FPS on it.

 

[JFrank]

Thanks I have not been back out to finish it. Too much to do or too much rain when I have time to fit in a field to shoot. The ladder steps all group about the same and only difference is as i go up the ladder in grains the groups creep up the target in the scope. When I get impatient the 4th round can drift if I try repeating ladder steps too fast.

If faster rounds are grouping is not the fastest ladder step that groups good the best load?

I have a separate target printed for each ladder step with 4 holes in it and date, bullet weight and assumed FPS on it.

Increased powder charges typically rise on paper but they can go left or right also. Look for point of impact stability not smallest group. You may be just shooting too close to see the tendencies.

 

[archeryrob]

Shooting at 100 yards. Most all typical hunting shots are 40 - 75 yards with a few 100- 150's spots and one 220 yard field at the most. Lots of grown thick stuff from an old Christmas tree farm they planted for the tax credit and never harvested dyeing off into Eastern woodland again. . Hunting the East rolling hills of the mountain valley doesn't have super long shots.

 

[thump_rrr]

I was doing some load development today with my Savage 110BA in 338 Lapua Magnum.
The total round count on this rifle since I bought it used 3 years ago is 135.
The guy before me said that he put 10 rounds through it before selling it to me.
I cleaned the rifle with wipe out when I purchased it
And once after putting 80 rounds through it.
Today I did a ladder with 24 rounds.
These were the last 6 rounds.

This was the Chrono data from the last 3 rounds.

 

[AJC1]

I go to the range with a clean rifle every time. If your not over a hundred rounds don't waste your time, energy, cleaner or components....

 

[NMexJim]

You can see group size fluctuations w/o a chrono, but you want to know max velocity spread and therefore standard deviation. Keeping velocity spreads down in the 10 to 15 fps ranges will give good load stability. If you can, get a chronograph of some kind.