Advice re: Loading 165 gr. TSX for .300WM

[wombat13]

I'm working up a load using IMR 4831 and the 165 gr. TSX for my .300WM. I came across this comment when scouring forums (not this one):

"I'm just mad that Barnes waters down their load data up to 5 1/2 grains of powder." A couple other posters agreed that older manuals had higher max charges listed.

Barnes shows 73.0 grains IMR 4831 as the max load. As I worked my way up, I found decent groups with 72 grains and 72.5 grains. The 72.8 grain group tightened up to 0.75" at 100 yards (4 shots), but then the 73.0 grain group opened up beyond 2". I also noticed primer flattening in the 73.0 grain group.

Two questions:

1. If older manuals did indeed show higher max loads, why have the newer manuals reduced them?
2. Is the flattening of primers and poorer group size an indication that my 73.0 gr load is approaching overpressure?

Thanks for any help.

 

[ironworkerwill]

I'd always favor the lowest published load especially for monometals.

It would be a good idea to consider flattening of primers as reaching over pressure. Its hard to say sight un seen. Other "tells" also indicates an over pressure situation.

Don't seat them in the lands. I wouldn't worry if it doesn't have mach 7 muzzle velocity as long as it shoots well.

 

[grubbylabs]

My personal philosophy is that less powder is better ( read that as cheaper to shoot). Especially in today's market where powder availability is hit and mis.

I think that most of the loaders who have been loading for at least a decade will tell you that the load data had been decreasing in general. I have never read and all inclusive answer as to why.

 

[wombat13]

I'd always favor the lowest published load especially for monometals.

It would be a good idea to consider flattening of primers as reaching over pressure. Its hard to say sight un seen. Other "tells" also indicates an over pressure situation.

Don't seat them in the lands. I wouldn't worry if it doesn't have mach 7 muzzle velocity as long as it shoots well.

Thanks for your comments. Barnes actually suggests a jump of at least 0.050" to the lands for the TSX. That works nicely for me because the magazine on my Ruger won't hold anything seated out to the lands.

Surprised you suggest lowest published charge for monometals. Can you tell me why? The only velocity recommendations I've seen for the TSX is "faster is better." Most seem to think they need to be driven fast to open up.

 

[gamestalker]

Primer appearance is only part of the picture. If you know the primer and cartridge from previous work ups, and bolt lift is good, you might not be over the top.

But from a reloading perspective, when you get good accuracy, you have reached your goal, unless your just wanting to break a fps record.

As for Barnes, I don't load much of them or any other monometals any more. They're more difficult and expensive to attain both, good velocity, and better than average accuracy with compared to a good cup and core, IMO.

GS

 

[ironworkerwill]

The lowest charge is the place to start because: they have a long bearing surface for weight, harder to engrave, reach max pressure with a lower charge, possibly safer and more forgiving. With the added benefit getting an extra shot or two per lb of "stuffing".

At magnum velocity I wouldn't worry about 100 fps.

I'm with GS. They are kinda pricy.

 

[gamestalker]

Some years back I got on a Barnes kick, having spent a small fortune working with them, I really gave them a fair chance. But in the end, I just can't justify using them, when a good quality bonded bullet will accomplish just as good, if not better performance, and at significantly less expense and time.

I tried them in numerous rifles and multiple chamberings, .270, 30-06. and 7mm RM. I could have probably completed 3+ typical high end velocity and accuracy developments with cup and core bullets, for about what it cost me in time and expense to develop for just one rifle with them. I'm not saying I didn't get them shooting well, but it was just so cumbersome and expensive, and I honestly never saw any real benefit in any respect.

GS

 

[wombat13]

Gamestalker wrote: "Primer appearance is only part of the picture. If you know the primer and cartridge from previous work ups, and bolt lift is good, you might not be over the top.

But from a reloading perspective, when you get good accuracy, you have reached your goal, unless your just wanting to break a fps record.

As for Barnes, I don't load much of them or any other monometals any more. They're more difficult and expensive to attain both, good velocity, and better than average accuracy with compared to a good cup and core, IMO."

Thanks for your comments. Of course, you're right - I've found a load with very good accuracy at 72.8 gr IMR 4831. 0.75" @ 100 yards with me on the trigger is an excellent group. I don't really need more velocity, but just wondered if there might be a load beyond 73 gr that would return to good accuracy.

 

[wombat13]

The lowest charge is the place to start because: they have a long bearing surface for weight, harder to engrave, reach max pressure with a lower charge, possibly safer and more forgiving. With the added benefit getting an extra shot or two per lb of "stuffing".

At magnum velocity I wouldn't worry about 100 fps.

I'm with GS. They are kinda pricy.

I started with the published starting load and worked my way up firing 2 shots @ 69 gr, 2 @ 70, 2 @ 71 checking for pressure signs at each shot. I shot groups with 72, 72.5, 72.8, and 73.0.

I understand what you're saying about not worrying about velocity and saving some powder. That's good advice, but I figure I should just buy a .30-06 or .308 if I'm worried about saving powder.

 

[wombat13]

Some years back I got on a Barnes kick, having spent a small fortune working with them, I really gave them a fair chance. But in the end, I just can't justify using them, when a good quality bonded bullet will accomplish just as good, if not better performance, and at significantly less expense and time.

I tried them in numerous rifles and multiple chamberings, .270, 30-06. and 7mm RM. I could have probably completed 3+ typical high end velocity and accuracy developments with cup and core bullets, for about what it cost me in time and expense to develop for just one rifle with them. I'm not saying I didn't get them shooting well, but it was just so cumbersome and expensive, and I honestly never saw any real benefit in any respect.

GS

I guess I just got lucky. This has been the easiest load development I've ever done. Barnes lists IMR 4831 as the most accurate powder for the 165 gr TSX in .300wm so that's what I started with. I seated the bullets so they'll fit in the magazine. Used the primers I have available and just varied the charge weight.

Prior to this I've tried three different bullets (Nosler BT, Hornady SST, Sierra GK) and three different powders (IMR 4831, Hybrid 100V, RL22) and the best combo I found was the 180gr NBT with 76.5 grains RL22 (slight better than 1" at 100 yards). I didn't play much with seating depth because the Ruger's magazine is so short it doesn't allow seating close the lands.

 

[gamestalker]

Well, that's good then. If you've found what your looking for without having to burn through a bunch of powder, and waste a bunch of bullets, then you've done well. I was never that fortunate to reach my accuracy and velocity goal with those bullets that quickly.

FYI, another great combination for me with the 300 WM, is 165 gr. Speer Hot Cores and IMR-7828. I did a recent development with those components, what I ended up with was amazing, IMO.. I got well under 1" accuracy at 81.8 grs. with the bullets seated right on the lands, and velocity was around 3100 fps.. But I continued working the charge up, as I worked up, the group kept closing more, at 83.0 grs. the group got so tight that I could barely see the ragged edges of the 5 shot group through the spotting scope at 100 yds.. Also velocity was consistently over 3200 fps., and didn't vary much at all. Here's the kicker, at 83.0 grs. which is max in Speer, there was nothing to indicate that pressures were getting up there. No primer flow to the edges of the pocket, bolt lift was normal, very pleasing for a max load.

Though I'm a huge fan of RL22, it didn't cooperate as nicely, though groups were very good, I had to push the pressure envelope to get close to what IMR-7828 did. I also ran IMR-4350 and H4831, but I couldn't get better than 1"-ish, and velocity came with a pressure price tag. I didn't have enough IMR-4831 to work with, but plan to check it out also when I get back to that project.

GS

 

[wombat13]

Gamestalker: funny you mention IMR 7828. I wanted to try it, but couldn't get my hands on any around here. I need to do some reading on pressure signs. The only thing I noticed was the start of primer flattening at 73gr. Is it at all likely that the groups will tighten up again if I push past 73 (while being vigilant for pressure signs)?

 

[gamestalker]

There is almost always at least two accuracy nodes, one is usually down below mid table, or near the start charge, and one up near or at the max. charge. So if pressures are holding ok, you might find a good group at 73.0 grs.. With RL22 I have often found really good accuracy up near max, but I have found pressures do get up there pretty good with 300 WM with that powder, which is why I'm now really liking 7828 so much for this combination.

As for pressure signs, if you've correlated primer appearance with bolt lift, extractor button transfer marks, and chrony results, you should know by flow appearance if your getting up there. But not all primers and brass are created equal, thus you could be mislead to think that you are either into high pressure territory, or you may not be as high as you think. An example of this, is using Win, R.P. and Federal brass, the same load will leave extractor button marks on the R.P. brass, but not on the Federal or Win. brass. However, bolt lift, primer flow and chrony numbers will indicate a good normal operating pressure, thus RP gives a false indication of excessive pressures. This is something I have consistently experienced with every cartridge, chambering, and in every rifle I load for.

So in retrospect, one should know how the components reflect pressures. IMO, and unfortunately, the only way to do this, is to do complete work ups with various head stamps, and stick to one primer brand. But as long as you are vigilant in watching for definitive signs, all of them, and you work up in small increments of no more than .2 grs., you'll learn how to recognize pressures, high or low. I also recommend working with slow burning powders while in the learning curve, they are much less spikey.

And of course another major player is head stamp, in that some brass is thicker and will run higher pressures than others. This is easily maintained by sticking to one head stamp per work up. I don't use a load worked up in a different head stamp, without starting over at a reasonable place in the table, pressures can jump surprisingly high due to heavier / thicker brass.

Hope this helps.

GS