Re-thinking 300 Win mag.

[kilotanker22]

So I have spent some time now testing various bullets with different charge weights with Reloder 26 in my 300 win mag. Accuracy is ok at best. once in awhile it all holds together, but not satisfactory really.

Velocity is very high (beating book loads by 100-200 FPS) without exceeding maximum loads. The problem I am having with reloder 26 is that by the time I get the velocity into a range where I would like it to be. (165 grain at 3200, 180 at 3050, and 200 grain at 2900-2950. I am starting to lose case fill. I also have not loaded it down below my initial ladder tests.

I was thinking that I may change the powder. I was thinking that a 165 grain bullet in front of some H-4350 or IMR 4451 would get me down around the velocity I am looking for and although the case fill will be a little less. The increased pressure due to the faster powder can maybe make up for that?

Also, I really wanted to use the 180 grain Sierra SBT, but I couldnt get that bullet to shoot at all in this rifle. More like a pattern than a group.

I have a feeling that The higher velocity may be part of the problem making none of my loads shoot the way They should. Also the rifle has a pretty long throat and I had to modify the magazine in order to be able to get anywhere near the lands. The 180 grain Sierra on the lands is not held by the case mouth anywhere near enough.. Nor is the 165 grain Game king HPBT Although I can get them a lot closer to the lands in the mag without destroying the bullet tip under recoil.

The 200 grain ELDX shoots ok, but even at .130 off the lands I am still loaded to 3.4"

So anyway. I am thinking that I want to slow my projectiles down to around where Factory ammunition velocities are. To give you an idea. I have no signs of pressure on brass or primers. No hard lift or extraction even in the slightest. 165 grain HPBT Game King is clocking in at 3380 FPS, 180 grain SBT coming in at 3195, 200 grain eldx is clocking at 3090 avg. This was from my most recent trip to the range. 60 degrees F.. I saw about a 30 FPS increase in velocity from a 30 degree increase in temperature. So about 1 fps per degree F.

Factory 180 grain Remington Corelokt ammunition was the best shooting so far. And it was 250 fps slower at 2945 AVG velocity. That is kind of what was leading me to believe that I need to change powder and slow these bullets down.

Powders I have available are RL 26, 25, 17. H-4350, Imr-4451, H-1000.

I am thinking I want to shoot either 4350 or 4451.

[LineStretcher]

Backdown your COL to what the CoreLokt was and try the 4350. Sometimes a little slower powder in a magnum is better. I use US 869 in my Weatherby's and have been getting some crazy good groups with my 6.5-300 Wby Mag and my 300 WBY Mag. I tried it on a whim and it's one of those things that you don't expect to work but it does.

[kilotanker22]

The reloder 26 is a good bit slower than the other powders, but I get what you are saying.

With the 200 grain ELDX I can not seat them that deeply. Or the entire bearing surface would be inside the case mouth

The 165 grain HPBT Game King ends up being pretty close. And the 180 grain SBT has the same CBTO measurement as the 165, but the bullet is about .040 longer. To seat the as deeply as the Core lokt was The 180 grain SBT would be way way from the lands. The corelokt although pointed has a flat tip.

[std7mag]

Kilo,
As i've previously mentioned, use the RL25 for fertilizer. Gives almost same velocities as RL26, but accuracy, wise ummm, leaves much to be desired.
Don't know what it is about it, just is.

Your 4350, 4451, RL17 aren't gonna give you decent case fill, at least on the 300 Win Mag.
While i haven't tried H1000, would probably be your best powder out of what you have.

RL22, and the 4831 powders should work decently.
RL23 would probably work really well for that case volume.

Again, quit getting hung up on speed, find your accuracy.
Speed without accuracy, you might as well throw rocks.

[kilotanker22]

I don't disagree. Although Reloder 25 has shot as accurately as reloder 26 in this rifle. Although the ES and SD were much higher than with reloder 26.

[Pathfinder45]

It could be more of a rifle problem than an ammo problem. Tell us about the rifle.

[RC20]

Any reason not to single load for a target accuracy load? Hunting of course you would want some in the magazine.

I would suggest you go to the low end and work up in .5 gr increment. You should find at least one or two nodes between low and medium high that shoot well.

I load 10 each when I do that and use bullets it likes and seated where it likes them.

If I hit a node soon then I keep testing to see if there is another one.

[kilotanker22]

Originally Posted by RC20

Any reason not to single load for a target accuracy load? Hunting of course you would want some in the magazine.

I would suggest you go to the low end and work up in .5 gr increment. You should find at least one or two nodes between low and medium high that shoot well.

I load 10 each when I do that and use bullets it likes and seated where it likes them.

If I hit a node soon then I keep testing to see if there is another one.

Yeah I think that is where I am at with this. I have used several ladder tests. Which have worked ok.

I am close to max listed charges with this rifle. And I have a pretty good idea of what is safe in it. I am not gonna start from the bottom, because that would take several pounds of powder and hundreds of bullets. For example. With RL 26 I would have to drop my charge weight by 16 grains from where I am now. Now if I did a ladder test the way I think that you are explaining then it would only take 32 rounds to load the entire load range. Although it would be less, because I am looking to drop 150 fps from each loading. So I would top out about a grain less than I am now.

Am I understanding you correctly RC20? Load 1 round of each in .5 grain increments? and then shoot them and find and accuracy node across the groups? Watching for changes in POI relative to POA? Similar to an OCW method?

[kilotanker22]

I am sorry RC20. I thought that you said you load 1 each. I see now that you said 10 each...

[Stats Shooter]

I have been dealing with a few .300wm's for a few years now. I can give you some general guide lines that might help you decide what to do.

With the hornady eld's, nosler accubond, and other bullets of this ilk, best results were 20 - 60 thousandths jump. With the sierra match king/game king type bullets they were less sensitive, but still were best in that 20 - 60 thousandths range.

I tried RL 25 and wound up with huge velocity changes based upon warm barrels vs. cold barrel and warm day vs cold day.

Tried Retumbo but found it too slow and too much powder compression.

Tried H4831 and Like it for light bullets below 180 grains....I use the long cut to fill the case better

H1000 is king for anything 180 and up with SD's in the single digits and ES's below 20. Also it is pretty temp stable.

Tried IMR 7828 after H1000 and while I got a bit better velocities, it was not as consistent.

My model 70 super grade is a 300wm for elk. I load the 200 gr nosler partition rather than the accubond. The reason is that the accubond would not shoot in this rifle at an OAL of 3.39 which is 0.01" shorter than the magazine's maximum. The partition is considerably shorter, about .15" or so and enough such that I could get it closer to the lands. Also, it isn't that jump sensitive anyway being a tangent ogive.

In my F-open .300wm I use the 225 gr hornady ELD-M but it is at an OAL of 3.63" OAL and 0.015" off the lands......would not cycle in any hunting rifle I am aware of, and it barely cycles in my AICS system I have for this rifle.

Going with shorter lighter bullets will help get you closer to the lands, the noses are going to be shorter.

[kilotanker22]

I bought some Hornady 168 grains HPBT match just to try with it today. I also have some 165 grain Sierra HPBT Gamekings that I would really like to find a good load for. With RL 26 they are shooting a little over an inch.

[Jack Ryan]

What the heck does this mean? "I am starting to lose case fill."

If you velocity is exceeding the book, you are loading them too hot or doing something else to raise the pressure. Lower your powder charge until you figure out what else it might be.

[kilotanker22]

Originally Posted by Jack Ryan

What the heck does this mean? "I am starting to lose case fill."

If you velocity is exceeding the book, you are loading them too hot or doing something else to raise the pressure. Lower your powder charge until you figure out what else it might be.

Well I do have 2 extra inches of barrel length over load data velocities. It seems to me that the slower powders in more overbore cartridges gain more ground with an increase in barrel length than cartridges using a lower amount of faster powders.

I am using cci 250 primers when most of my data used WLRM. I have seen primer make a difference and yield an increase in velocity, But I doubt that much.

Remington Brass, which does have slightly less case volume than other brass most of the time.

I am neck sizing each time. Bullets are all seated further out of the case than any of the load data loads. And still seated plenty far from the lands.

Factory ammunition basically yielded advertised velocity.
H-1000 Yielded almost identical to book values with 1 load.

Reloder 25 yielded about a 100 FPS faster than book velocity with 200 grain bullets.

Reloder 26 is more with 165 grain bullets. I am a full grain below the listed data and I am getting 100 plus fps over their listed max load.

Reloder 26 also gives me around 100 extra fps in all 3 6.5 creedmoor rifles. With the 22 and 24 inch barrels having 100 fps difference in velocity for 2 inches.

all of those same rifles showed only about 50 fps for 2 inches of barrel length increase with H-4350.

So with the reloder 26 powder. I assume that with overbore cartridges like the 6.5 creedmoor through the really overbore cartridges. I expect to see about 50 fps per inch.

So I feel like taking that into account I am really only besting the velocity by 40-80 FPS..

I have no signs of pressure at all. Primers are still definitely round. No waves, no craters, no hard bolt lift or extraction. I have some brass that has been fired 5 times with no signs of failure or stress yet.

Now My brass shoulder position grew .015" at the first firing. That along with the bullet being seated further out of the case allows for more case volume Than Factory Load data. Also my bullets are plenty far off the lands to allow a start without spiking pressure like being on the lands would.

That along with the lack of pressure signs leads me to believe that I do not have a pressure problem. I kind of feel like It has more to do with harmonics than load consistency. Maybe that 26 inch sporter weight barrel is whipping a lot and I need to find a bullet and load that is leaving the bore at an optimum time. Which I also feel like I could manage by slowing them down. Although I have no evidence to base that theory on.

[sako2]

Kilo can you find rl16 up your way. When I was up to buy those bullets I was in another gun shop. I think it was academy sporting good they had a good bit of reloading supplies. Try that 4350 or rl16.

[kilotanker22]

Yeah I can get RL 16.

I already have 5 pounds of H 4350 and several pounds of ImR 4451. Nothin that same area for burn rate. Imr 4451 is a little more bulky that the H4350 though.

[kilotanker22]

I just traded that 300 win mag for an older Remington 700 in 270 wsm. But new in box.

[sako2]

Good luck with the new rifle.

[RC20]

I am not gonna start from the bottom, because that would take several pounds of powder and hundreds of bullets. F

I hate to tell you this but that is most of the fun!

I don't have range access that allows the needed 200 yards or better for ladder so I go with the 10 rounds in 5/10 increments.

[kilotanker22]

I also picked up a Remington 700 5R gen 2 in 308 Win. Well. Picking them up tomorrow. I wanted another 308 caliber rifle, because I have a ton of bullets. Now I just need dies and some suitable powder for the 308. Pretty much everything I have is way too slow

[Charlie98]

Now I just need dies and some suitable powder for the 308.

I've been working up loads for my Savage 10T in .308 with the 168grn bullet... so far IMR4064 has been the clear winner, even over IMR4895. I've also found you get what you pay for... the SMK is far more accurate in two different rifles over the Nosler CC.

[F. Guffey]

I took two new 300 Winchester Mags to the range, both using the same ammo. With a little work one of the rifles shot 'one hole groups', the other never got better than shooting something that looked like shot gun patterns.

the rifle was sent back to Winchester, they sent the rifle back in a new box. I have had it for close to 15 years, I thought about taking it to the firing range and then I got over the urge. I built a 7MM Remington Mag and found a few bench rest type barrels in 308W and 8MM 338Mag.

F. Guffey