[blarby]

Ok, here's a question :

For some reason, winchester factory ammo shoots really well in the wifes' new gun. Not perfect, but well enough that I think its an indicator of where to start the workup in the " on the lands/ off the lands" argument.

To get 145g BTSP's by Speer to match that Ogive Length as a starting point, this puts the COAL at about 2.649.

Speers load data Shows a COAL tested at 2.730, using RL 19.

Do you believe this would cause any pressure issues at starting loads ?


Not trying to completely sidestep the load dev process, and I plan to go up and down from here, but the handy win load could potentially save me a lot of "up and down" on the lands seating issues.

Thoughts'd be helpful !

[blarby]

MAybe useless after all- She wants to start at the lands !

[Flintknapper]

Without knowing the actual bullet length (component part) I can't give you an accurate figure, but substituting that bullet for a 150 Nosler, QuickLoad shows a difference of about 4,000 psi between the two COAL's.

Your bullet would be similar. So take that into account when you decide on your start load.

I like Reloder-15 much better than 19 for the 7mm-08.

[gamestalker]

RL19 is a nice slower burning powder for that cartridge and should do fine. Start on the lower end of the data, and then seat as I decribed below.

I would seat one that is consistently touching the lands, not into them though. Then I would increase the depth until you are certain it is not touching, then lock your die down to that depth. Load a few up at that depth, 10 should be enough to get an idea of how they group while checking extraction reistence for pressure signs, which shouldn't be abnormal if your not touching.

If all looks OK, I would then begin an incremental increase in powder charge if necessary / desired, but RL19 even on the low end should produce pretty nice velocities.

Most all my high powered rifle bullets touch the lands, but I always work form the lower end of the powder charges with slow burning powders too. Touching the lands can improve accuracy, but pressures can spike if starting at too high of a charge.

GS

[blarby]

Luckily, finding the lands wasn't real difficult using the precision mic.

Ive got 25 made at the lands, and i'm gonna do 2-4 shot strings at -.005 to -.030 and see where we end up. I've had the chance now to see some of the data using upper ends of RL19 charges moving into the lands....and it wasn't very impressive, and some of it looked downright dangerous after about +.015

Although its great that the winchester ammo runs pretty good, I'm not happy that getting to that Ogive length using these bullets and RL19 is quite compressed. I don't have a lot of room for powder charge development at that depth. You can hear the powder cracklin and crunchin when ya seat 'em.

As it turns out, the winchester ammo is -.097 to -.099 off the lands.... thats pretty deep. I hope we don't have to run that deep to find similar accuracy, as thats a lot (comparatively) of jump to me.

[Flintknapper]

^^^^^^^^^^

That's why I suggested Reloder-15.

RL-17 will make a nice soft shooting load at marginal velocity, but you can't get it up into 2700-2800 range without compressing significantly.


Use RL-15, if you want to stay with the "reloder" series....or a handful of other powders I can suggest.

Everyone's rifle is different....but I haven't found any accuracy gains by loading up to lands in my 7mm-08 and I've been experimenting with it for over 10 yrs.

[blarby]

Its a new rifle for the wife, so she calls the shots.... I just squish the bullets on her orders.

We'll see what we get !

[Flintknapper]

I just squish the bullets on her orders.

I understand. ;)


If you need someone to run some QuickLoad numbers for you, let me know.

I just need certain information.

[blarby]

Always helpful, that software.

What kind of info do ya need ?

[Flintknapper]

What kind of info do ya need ?

Bullet length (the component part) very important.

Bullet Weight (145 gr. in this case)

Trimmed length of Cartridge Case

Overall length of Loaded round (COAL)

Powder type and charge weight, or give me the desired velocity range and I can give you predictions on pressure and/or suggest other powders you can use.

[blarby]

I'll get the COAL to ya once we find what works best for the rifle.

Thanks for your help !

[blarby]

Bullet length (the component part) very important. 1.160"

Bullet Weight (145 gr. in this case) 145gr

Trimmed length of Cartridge Case 2.0315"

Overall length of Loaded round (COAL)2.7415"-2.742"

47grs RL17

CCI LRP

Thank you very much !

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc7/306911_411110455597006_688469114_n.jpg

[Flintknapper]

^^^^^^^^^^^^^ Excellent photo!

[blarby]

Im sorry, I misquoted RL17 too.... its RL19 !

We are having the same mental issues !

[Flintknapper]

In that case you are fine.

47.0 grains of RL-19 gives you 106% case fill (medium compression) at a predicted 2675 fps (based on a 22" barrel), 2305 ft. lbs energy, 49,894 Pressure, with 92.4% powder burn.

So, while you are not Maxed out for pressure...you are limited (for practical purposes) by the case fill.

RL-17 is a more efficient powder for that loading, or even RL-15.

In fact here is a short list of powders you can try that will get you from about 2,600 fps up to roughly 2800 fps at various pressures (all safe), But always ladder up.


Cartridge: 7 mm-08 Rem.
Bullet: .284, 145 gr. Speer #1628
Cartridge O.A.L.: 2.741 inch
Barrel Length: 22.0 inch



Powder type Fill/Ratio Charge Vel. Prop.Burnt P max
% Grains fps % psi
--------------------------------- -----------------------------------------------------------------
Alliant Reloder-17 97.9 45.4 2824 99.5 58000
Vihtavuori N550 103.1 46.6 2816 98.8 58000
IMR 4895 95.3 42.2 2787 99.7 58000
Alliant Reloder-15 96.1 42.5 2776 99.4 58000
IMR 3031 95.8 39.6 2757 100.0 58000
Hodgdon VARGET 98.5 42.2 2737 99.3 58000
IMR 4350 105.0 46.2 2729 95.7 58000
Vihtavuori N150 105.0 43.8 2710 100.0 58000
Alliant Reloder-19 105.0 46.4 2640 91.8 47938
Vihtavuori N130 89.4 37.0 2622 100.0 58000

[blarby]

Which is odd, because when it sits in the cases, its not full.

I do sort my cases by grain weight, and these are the lightest ones....wonder how that effects it.

Using this seat length/depth, its not crunchy :)

[Flintknapper]

Which is odd, because when it sits in the cases, its not full.
Its not "full" in the sense that it fills the case (to the mouth), but 'full' in the sense that the remaining case capacity (with bullet in place) is less than the powder charge (just slightly). With extruded powders...you can usually tap the cases (or use a long funnel) to settle the powder charge...if you like.

I do sort my cases by grain weight, and these are the lightest ones....wonder how that effects it.
The lighter ones might have slightly more capacity...but the difference would be so small...as not to matter...unless you are a bench rest shooter.

Using this seat length/depth, its not crunchy
Powder might have settled and you just aren't hearing it. It is very lightly compressed (nothing wrong with that).

Maximum case capacity (to overflow) H2o is 55.0 grains.

[blarby]

Thanks for all the input !

Seems like it'd be really hard to go dangerously overpressure with RL19 in this cartridge without serious compression....like hydraulic compression.

[GooseGestapo]

I've tried three different lot#'s of RL19 in the 7mm08 and never got either the accuracy or velocities suggested. I've ended up shooting it up from a .338/06 which actually gets the Speer manual velocities and decent accuracy for the 225gr bullets....

However, with RL17, I hit the jack-pot. With my 20"bbl Rem. Mod-7, I get 2,800fps with the 150's (45.0gr) and excellent accuracy. (as good as my gun will shoot--- 1.5-2.0moa).
I get better velocity and accuracy with RL17 than any other powder. IMR4350 was the previous prefered powder. Velocity was slightly lower and accuracy about the same. My gun "gags" on H4350 and H414. (3moa+).

FWIW; Winchester loads the factory 7mm08 with non-cannister versions of Win760/H414. To duplicate factory ammo, I'd start there. I get "factory" velocities and accuracy with it. Accuracy isn't anything to brag about though...