I've been working on loads for a friend of mine. My standard has been 53.5 gr of IMR-4350 @ 3.34" Superb accuracy, but a little slow around 2,575 fps. This is from a 22.4" barrel. Load is max capacity.

I tried some RL-17 this past weekend at same COL and 54.5 and 55 gr. 55 gr was about max capacity. Got 2,804 fps and 2,833 fps respectively with no pressure signs, but didn't group.

First thing I noticed was that the IMR-4350 results were well below all the book #s and software #s in terms of speed. The RL-17 were higher.

I'm going to try to lighter RL-17 loads and see if I can get goot velocity and groups - looking for 2,700 fps.

Any thoughts on the big velocity swing on these powders? I also have Varget, 203B, IMR-4064, RL-22, RL-25, MRP, H-4350, and IMR-7828 SSC that I could try.

I like imr 4831 for my 30-06 Cooper. My load is 56.4 gr at 2800fps with 180 gr Sierra bt but your gun may need more or less powder. This load is always moa or less out of this gun.

Austin Hunter:

I use magnum primers (Federal GM215M) with RL-17 in both 8x57 Mauser (196gr bullet) and .375 H&H (300gr bullet). In both calibers, I use compressed loads. Accuracy is just great.


Jiri

I thought about trying a magnum primer with the IMR-4350.

I would give the IMR 4064 or H4350 a try. From what I can see is that your IMR 4350 is doing just what the books say it should do. roger

I have had good luck with H3450 and RL 22, although the RL 22 can be hard to compress the max load in.

Swift Scirocco's have a secant ogive and are sensitive to seating depth (ie., distance for the lands) for accuracy.

Before you discard this load, which looks great, consider loading 24 rounds at the following 4 different COAL's, if you're not worried about jamming the bullet into the lands of the rifling...

0.010" into the (touching) the lands, 6 rounds
0.030" off the lands (jump), 6 rounds
0.070" off the lands, 6 rounds
0.110" off the lands, 6 rounds

If you don't want to jam the bullet, try...

0.010" off the lands (jump), 6 rounds
0.050" off the lands, 6 rounds
0.090" off the lands, 6 rounds
0.130" off the lands, 6 rounds

Shoot two sets of 3-shot groups each. One group is likely to outperform the others. Now you can futher tweak the COAL +/- 0.005" until you optimize your COAL.

This is from Berger Bullets, whom make a lot of secant ogive VLD bullets. This is their recommended approach for jump-distance sensitive secant ogive bullets.

The COAL length of 3.34" works great for the IMR-4350, just velocity stinks.

Given it doesn't group with RL-17 at the same COAL, would changing the COAL make that much of a difference? I was going to start with some lighter loads of the RL-17 at the same length and then if that didn't work, go to a different powder.

quote:

Given it doesn't group with RL-17 at the same COAL, would changing the COAL make that much of a difference?

Hard to know with certainty, but a significant change in velocity may require a different COAL to achieve equal accuracy...???

IMO, adjusting the COAL is worth a try.

bump up you I4350 load a bit.

Several powders should give you good results with a 180 gr bullet. I would recommend CCI 250 primers and 56 or 57 grs of IMR 4350. Some rifle/bullet combinations seem to be fussy about seating depth of the bullet. I would not use a bullet seating that has the bullet jammed into the rifling. That will likely shoot but I have seen a bullet jammed into the rifling pull out of the case when an attempt to eject the round was made. Bullet jammed in barrel, powder all over the action and magazine....not good in a hunting situation. I would suggest you check the COL where the bullet touches the rifling. Then check the COL of a round that will function through the magazine reliably. If the reliable feeding round is shorter than the round that touches go with it.

If you have a 30-06 that will not shoot well with 56-57grs I4350 and any good 165gr bullet, or 55-56grs of I4350 and any good 180gr bullet, sell the rifle.

If I go above 53.5 gr, it will be a very compressed load. And I'm at 3.34" - magazine has a hair more room, not much.

How much do you guys compress loads?

I'm using Lapua brass, so maybe it's thicker?

I just worked up 2 loads using 165 Accubonds for the wife's 30-06 with a 20" barrel and my Sako A7. Using RL-22 with her gun 59 grains worked fantastic and my Sako liked 61 grains almost as well. Both guns shoot 3/4 inch groups or better.

I have had excellent velocity with RL-17, but some of my guns like it and some don't. Your idea to drop the powder charge a grain or two is a good one and is the first thing you should try.

H4350 is a denser powder (but very slightly slower burning) than IMR-4350. You can get more of it into the case, so if your RL-17 doesn't pan out I'd suggest trying it first. RL-22 will provide surprising velocities with the 180 in a .30-06, but you'll probably need to compress it significantly.

As far as how much compression is too much, generally if (1) your bullet is deformed in seating, or (2) an uncrimped bullet works its way forward over time is the compression too much. So long as the bullet can be seated without undue force a little powder compression is usually a good thing as moderate powder compression usually results in more consistent ignition and shot-to-shot velocities.

Another suggestion: You can get similar terminal performance (and usually better accuracy) by using a Nosler Accubond in the place of the Scirocco. The Nosler uses a bit harder copper alloy on the jacket which doesn't leave as much copper behind in the bore as the very soft Scirocco jackets.

The one 30-06 that I'm using 180s in likes 56.5 grains of H4350. It has a 26" Benchmark barrel and puts out 2850 fps.

quote:

Originally posted by Austin Hunter:
If I go above 53.5 gr, it will be a very compressed load. And I'm at 3.34" - magazine has a hair more room, not much.

How much do you guys compress loads?

I'm using Lapua brass, so maybe it's thicker?

56 gr IMR4350 w/180s has been my '06 load since I was a kid. Never tried Lapua brass, but that charge works in all headstamps I have without compression (but see last paragraph).

Best and safest approach is to first weigh your brass alongside some WW and/or RP. Then measure internal capacity (can use IMR 4350 or water). I never cease to be amazed by how much variation in internal capacity can exist - got a real surprise comparing WBY vs RP .300 Roy brass.

Assuming Lapua brass internal capacity will allow you to use 56 gr, use gravity. A drop tube will allow you to pack the granules and avoid compressing. A simple soda straw works fine here. Again, I don't need this for '06 w/180s, but a drop tube is definitely needed to use IMR4350 in a .308 WCF. Alternatively, have used vibration during trickle charging to accomplish the same result. I much prefer these approaches to crunching granules during bullet seating.

I typically weight each charge for accuracy and then a funnel. I guess I could use a manual drop tube. I will also tap the filled case to settle the powder, that seems to work well.

Also, the 180's you are using, how long are they? The Scirocco's are 1.435"

quote:

Originally posted by Austin Hunter:
Also, the 180's you are using, how long are they? The Scirocco's are 1.435"

The longest 180s I load in '06 are Sierra 180 BTSPs, 1.288" nominally.

But my rifles are Win '54s and '70s and box length allows them to be seated well beyond nominal COL, which increases powder capacity. My dad's Ruger 77 has a more "typical" box mag length, but we stuff 56 gr IMR4350 in those shells, too. Guess if your rifle's mag length is more limiting COL requirements could impact max charge.

If you discover Lapua '06 internal capacity is relatively low maybe consider switching to something like Win brass? I would be interested in your findings on the Lapua brass weights vs other brands.

The best powder ever was old surplus 4831. It gave less pressure, more velocity and the best accuracy in every 30-06 I have owned..I still have a good supply of that stuff, but reserve it now for the .270...The stuff that Jack O'
connor used almost exclusively with IMR-4064 his second choice..

All that said and the powder is no more, I believe RL-22 and H-414 to be the best of todays powders all things considered and definatly the fastest, and RL-19 second..

These powders give me the best combination of velocity and accuracy and easy metering. I work up my own loads and reach every rifles full max so that I "know" where "that rifles" max actually is..then I normally cut back a grain or two to the most accurate load..Many times however the most accurate loads are max..

Today H and IMR 4831 are excellent powders as is H and IMR-4350, BUT they do not meter well and one should probably weigh every load, of which I am no longer inclined to do,but to each his own on that count.

quote:

Originally posted by Atkinson:
The best powder ever was old surplus 4831. It gave less pressure, more velocity and the best accuracy in every 30-06 I have owned..I still have a good supply of that stuff, but reserve it now for the .270...The stuff that Jack O'
connor used almost exclusively with IMR-4064 his second choice..

All that said and the powder is no more, I believe RL-22 and H-414 to be the best of todays powders all things considered and definatly the fastest, and RL-19 second..

These powders give me the best combination of velocity and accuracy and easy metering. I work up my own loads and reach every rifles full max so that I "know" where "that rifles" max actually is..then I normally cut back a grain or two to the most accurate load..Many times however the most accurate loads are max..

Today H and IMR 4831 are excellent powders as is H and IMR-4350, BUT they do not meter well and one should probably weigh every load, of which I am no longer inclined to do,but to each his own on that count.

When I'm loading a lot of ammo for shooting (not load development), I'll use a handle operated charger after I get it dialed in. I then throw all the loads and then go back and measure each one and target +/- .1 gr. If it's out of this range, I manually adjust. That is much faster than doing each on a scale.

quote:

Originally posted by Austin Hunter:

Also, the 180's you are using, how long are they? The Scirocco's are 1.435"

I just measured a couple of 180 Accubond bullets at 1.39"

These normally get pushed along with 56.0 grains of IMR 4350. 56.5 grains shows no pressure signs but my rifle shoots just a little bit tighter with 56.0 grains.

WAY back when, Rick Jameson did an article on thrown charges. IIRQ, his findings was it depended on the percentage of the total charge whether it would be an affect or not. A .5gr difference in a 30-06 load would have little or not effect where a .5gr difference could make a considerable difference in say a .222.