Ways to raise velocity from established load?

[Boyscout618]

Rifle: semi-custom Remington 700 7mm-08 Varmint, 26" 1-9.25 barrel, ~400 rounds through
Load: Winchester brass and primers, 36.5gr Varget, 162gr ELD-M loaded .015" off the lands = 2400 fps, SD in low-teens

I developed this load with the ladder test method at 300yds and it has been very consistent and accurate for me, by my standards (.75-.5 MOA if not better, still more accurate than I am). The problem, or dilemma I guess, is that it's going pretty slow. During testing I started seeing pressure signs around 38.0gr, just flattened/cratered primers. My questions is: where should I begin to get higher velocities, or should I leave well enough alone? I plan on trying different powders when I run out of Varget, but where should I start? Or should I try different bullets, like Berger VLDs? I've noticed the wind pushes it a good amount at range, that's where the basis of this question comes from. Keep in mind, my pockets aren't as deep as some other shooters out there.

Dope, tested and confirmed:
300: -1.5 mils
600: -4.9 mils
800: -7.8 mils
1000: -11.5 mils

Thanks all, I appreciate the help!

 

[maggitas]

Boyscout,

If you change anything with your recipe to gain speed then you will probably lose your accuracy. IMR Load data says your starting point for a 162 gr load should be 38.5 grains of varget and should stop at 41 grains. Perhaps your load is closer to the lands than you think and that is why you are seeing pressure signs. I would suggest working up a load looking for a higher node running the rounds at the COAL of 2.875

 

[Carl_Ross]

Your load is pretty soft, your pressure signs aren’t coming from too much powder. That combo should get you in the 2650-2700 neighborhood, if you take it to full pressure. Possibly you have excess headspace on your brass, how are you adjusting your sizing die?

Also, is this a factory chamber?

 

[Boyscout618]

So the chamber is something that threw me through a loop. Doing the old fashioned method of taking a test brass, chambering with a loose bullet, and reading the OAL, I came out way over mag length, to the tune of 2.976 to set the bullet in place with the lands. I tested this multiple times, it's how I was taught and how I've done every load I've worked up. Taking off .015 = 2.961, which is the OAL I've been using. As far as I know the chamber is factory; however the barrel was taken off the action, if it ever had one from factory, and was threaded into an old action, from a Remington "Sportsman 78," which I've talked about a bit on this site. Somewhere in this process it may not have been set to the proper length...? I'm no gunsmith.

For brass prep I tumble, then resize/deprime with full-size die. Going off research and suggestions from Sierra's reloading book, I set the resizing die so it touched the shell holder with the ram all the way up, and then checked and adjusted until I felt tension re-chambering each new piece of brass every time I backed it off. HOWEVER, I didn't feel any tension in the chamber until I had backed the die so far out it was no longer punching out the spent primer. I currently have it set so it just punches out the primer, and based off the marking of the brass it resizes about 3/4 of the neck. Essentially, I am creating the effect of neck sizing. I haven't had any issues with chambering any brass, or pressure signs from the 100 or so rounds that I've sized this way.

I then trim all brass to 2.030, which is directly between the trim-to length and case OAL per Sierra's reloading book.

I know that all probably sounds janky and some pro's are tearing out their hair reading that, but the accuracy results don't lie. I know there are more accurate tools to measure and set, but I'm still learning and doing things the way I was taught before attempting to learn too much at once.

 

[spife7980]

That does def sound janky. If it were me I would get a go gauge and add tape to it until you can’t get the bolt to close and measure how much headspace you actually have or take it to a smith to do it. Just for piece of mind.

Get a pair of caliper and hornady/Sinclair headspace comparators and start measuring to see just how far out you are from a safe spec. You could have lucked out or you could be playing with fire. Especially if the barrel was chambered for another action.

As for more velocity get a double base powder (alliant) vs your single base (hodgdon). Just be careful as hell because you dont really know what exactly youre working with until you actually measure.

 

[Carl_Ross]

Your brass is likely quite loose in your chamber, which can cause pressure signs by itself. I assume a bolt closes without resistance on fired brass?

If so, the scotch tape trick spife mentioned isn't the worst place to start, It's roughly .002" per layer of tape. This should give you a clue as to how your brass is fitting. If there is a spent primer proud of the case head remove it first.

Your decapping rod to remove the spent primer should be adjusted independent of setting the die appropriately. Getting your die to size your brass properly is goal #1 by far, only then screw with the decapping rod till it does its job as well. My guess is your brass is loose to the chamber after being fired, then when you size it with the die backed way off, the sides of the case are compressed in by the die before the shoulder is touched, and this compression actually moves the shoulder forward. You can use this to establish headspace control, which is what I'd do. Then I'd add powder till you were at speed, at which point your cases should come out of the chamber actually needing to be full length sized. At this point you can fine tune your load around the greater speed, and once all your brass is "fireformed" to your gun, adjust your sizing die to set the shoulder to an appropriate fit to your chamber.

 

[Jedi]

Get chamber measured by a good smith or do it your self if your confident in your ability to do so
Barrel may need set back slightly, easy job for competent smith

I never FL size brass for my bolt gun, rarely if ever trim brass. I do know my chambers exact measurements however

Factory chambers generally are on the loose side with long OAL

QuickLOAD is $$ well spent

 

[mi223]

I agree checking the headspace would definitely be some peace of mind but the the biggest issue i see is not properly adjusting the sizing die. Even if the chamber is not to spec he should be able to bump the shoulder back .002 on brass fired in that chamber.

Op you need a way to measure your shoulder dimension. A Hornady or Sinclair case gage is best but do a Google search for alternatives if money is that tight. I remember someone using a pistol case as a gage somewhere. You will need a caliper with any of these. There is no way around that.

If you bump the shoulder back .002 and set the bullet so it has a .02 jump you should be able to increase your powder.

Sent from my SM-G930P using Tapatalk

 

[Yondering]

Op you need a way to measure your shoulder dimension. A Hornady or Sinclair case gage is best but do a Google search for alternatives if money is that tight. I remember someone using a pistol case as a gage somewhere. You will need a caliper with any of these. There is no way around that.

It's been said already but can't be overstated, you really need a way to measure the shoulder dimension (headspace) in that setup. As you describe it now, it really is janky as you say; you're just groping in the dark until you measure how much you're bumping shoulders back.

Also, don't adjust the sizing die body based on where it punches primers out. That's a separate adjustment of the stem.

Here's a visual on measuring the shoulder dimension. This pic shows the measurement of sized brass, after the calipers are zeroed on fired brass. Punch out the primer without resizing the fired brass to set the initial zero; any crater in the primer will give you a false zero otherwise.
The adapter is essentially just a tube of the right inner diameter, and can be anything from a 9mm case to a Hornady comparator to a piece you make yourself, like mine.

 

[MtnCreek]

Not addressing possible head clearance issues here.

Push the load (somewhat safely) to the point of ruining brass in a firing or two would be one way. Seeing if you could get enough of a slower powder in the case would be another.

 

[Wayne McNeely]

Ok, first off with your once fired brass from your chamber, check to see if you can feel the slightest drag while closing the bolt on a fired case. Since the load is pretty light, chances are you can’t. So, loosen the jam nut on the decamping stem, and leave it loose. Next loosen the jam screw on the lock ring on the die. Take a sharpie and black in the shoulder on one case and hand lube just the case body. With the die turned back one complete turn from the original setting, run the lubed and marked case all the way in and back out. If the primer wasn’t popped out run the stem down one turn. Check to see if the shoulder was touched. If not, relube and turn the die down 1/4 turn and run it in again. Continue this until you’ve touched the shoulder. Lock your die down there as you’ve achieved pretty close to perfect headspace for your chamber.
Now with that out of the way you’ll need to try a new powder. I would recommend either Reloader-17 or Hogdon’s H-4350. Maintain the same seating depth, and do a ladder test to istablish a good load that should get you near 2650 FPS.

good luck,

Wayne

 

[Yondering]

If not, relube and turn the die down 1/4 turn and run it in again.

NO no no. Wayne do you realize how much headspace changes with 1/4 turn of a die? (Hint - way more than is acceptable)

 

[MtnCreek]

About 18 thou.

 

[Wayne McNeely]

NO no no. Wayne do you realize how much headspace changes with 1/4 turn of a die? (Hint - way more than is acceptable)

Your entirely right, that was meant to read 1/8 turn, which is the way I was taught. Thanks for keeping me straight!

Wayne

 

[Sheldon N]

Again, don't do that. 1/8 turn is 9 thou of headspace. That's the difference between brass won't chamber and a rapid brass death from case head separation.

Get a set of Hornady comparator tools, or even just turn an empty .40 cal case upside down and use that as a comparator. Measure and do it right.

 

[Boyscout618]

Thanks everyone for all of the suggestions. Sounds like I will be ordering a headspace gauge and doing some fiddling with it. Nebie move, I didn't know the primer punch could be individually adjusted, so that's good to know. I just ordered fresh brass to start from scratch, that should help me figure out what's what. Thanks again!

 

[Yondering]

Your entirely right, that was meant to read 1/8 turn, which is the way I was taught. Thanks for keeping me straight!

Wayne

I was taught 1/8 turn too, but even that's too much. The fact that it's often "close enough" is testament to quality control of the die makers and firearm manufacturers, but sometimes (like the OP's case) the simple method doesn't work out like it should.

In full disclosure - years ago once I started measuring headspace as pictured above, I was shocked by how far wrong some of my old die settings were. I can't in good conscience recommend the 1/8 turn method any more, especially when someone appears to be having headspace problems. There's no substitute for proper measurements.