StaBall 6.5

[LolaPP]

I'm never, ever an early adopter, but after eye banging the load data for a few nights I rolled the dice on 8 lbs of SB 6.5. I didn't think it was too much of a gamble. The published data was right there with loads that work great for me in 7-08 and .270 Win, and I liked the data for it a lot in other cartridges too.

I started with .270 Win. Used Sierra 140 TGKs, loaded five workup rounds to get me to max charge, the five at 1% over. That's provided outstanding performance in this rifle with powders either side of SB 6.5, so I figured I'd see how lucky I could get.



I like it. It does exactly what you think it'll do. Didn't run it over the chrono yet but it'll be right around 3000 fps. Based on that I'm looking forward to trying it in the other cartridges it's suited for. It'll actually let me eliminate a powder if it all works out.

 

[6MT]

.....

 

[LolaPP]

I am curious. What kind of barrel life can one expect with the 1% over load?

Just asking, not trying to be a jerk.

No, that's actually one of the questions I'm trying to answer. I'm confident it'll have more to do with the powder burned, than whether or not there's 1% more of it. I'm honestly not sure that any safe load you could get to will eat your barrel any faster than than a minimum load. There's just not that big a spread - well, 10% or so, right? My guess is that 1% over will eat your barrel exactly 1% faster than the max load. It just happens to be a charge where this rifle seems to have a node with several different bullets and powders. It's boringly predictable to load for, which is why I picked it here to see how SB 6.5 performed.

The rifle I'm shooting this through has about 1k rounds down the CrMo tube. I'm the only owner. I haven't babied it, but I've avoided cooking the barrel. That means I don't get it hotter than I can hold, which is a 5 to 10 shot string depending on ambient temp and rate of fire. Every round up to today has been with stick powder, which all things being equal will be harder on the bore than SB 6.5, SB 6.5 being double based and spherical.

Looking at the bore with a scope, I see some minor fire cracking for the first few inches, and minor but noticeable throat erosion. Luckily, I'm not out of mag length, so if accuracy dropped off and I wanted to seat out I still have a bit of room. We're nowhere near that yet though.

Given all that, and depending on what accuracy you'd accept, I would guess very roughly 4k rounds before it wasn't suitable for hunting deer sized game out to say 600 yards? I just don't know though, it'll depend on how the wear progresses. I really don't think the throat is more than 25% gone.

I'm happy with that out of a .270 Win. I don't know why I'd ever pick it over a 7mm-08 other than nostalgia, but you'd certainly be good for a lifetime or three of normal hunting use with it anyway.

 

[1899]

I was looking at this powder earlier tonight and wondering if anyone has actually tried it - specifically in the 7mm-08. Curious if it will live up to the marketing hype as some of the numbers look almost too good to be true:

150gr TTSX @ 2891 fps out of a 24" barrel and only 57,900 PSI would be amazing. Especially if it gives good accuracy and temperature stability.

Keep us posted.

 

[LolaPP]

I was looking at this powder earlier tonight and wondering if anyone has actually tried it - specifically in the 7mm-08. Curious if it will live up to the marketing hype as some of the numbers look almost too good to be true:

150gr TTSX @ 2891 fps out of a 24" barrel and only 57,900 PSI would be amazing. Especially if it gives good accuracy and temperature stability.

Keep us posted.

I'm pleasantly surprised in that it's totally unsurprising. I haven't tested for temp stability but don't really feel the need to, there's plenty of tests on YT and elsewhere. I believe it.

Unfortunately the 7mm08 I have is uniquely unsuited to this as it's a 18.5" Rem Seven. It's next to test it with though.

 

[todbartell]

There's some good info here on CGN and HuntingBC on StaBALL, do a search

It's proven to me to be a stable powder, and give good speed/accuracy. I'll be buying more when my 2lbs run low

 

[cbh560]

I was looking at this powder earlier tonight and wondering if anyone has actually tried it - specifically in the 7mm-08. Curious if it will live up to the marketing hype as some of the numbers look almost too good to be true:

150gr TTSX @ 2891 fps out of a 24" barrel and only 57,900 PSI would be amazing. Especially if it gives good accuracy and temperature stability.

Keep us posted.

I have tried it, albeit with a 7-08 AI and 140 Nosler Accubonds. I was running it through a 22" barrel and was capable of over 3000 fps, but was showing signs of pressure. I think it's quite possible that you could read 2900 with 150's out of a 24" barrel, but you'll likely be pushing the upper pressure limits

 

[1899]

I have tried it, albeit with a 7-08 AI and 140 Nosler Accubonds. I was running it through a 22" barrel and was capable of over 3000 fps, but was showing signs of pressure. I think it's quite possible that you could read 2900 with 150's out of a 24" barrel, but you'll likely be pushing the upper pressure limits

That's the point - factory data shows those numbers with a low 57,900 PSI (SAAMI max is 61,000 PSI). Or 162 A-Max at 2821 fps and 59,000 PSI.

Like I said, almost sounds too good to be true.

Mark - picked up 6 pounds of RL26 from you guys a couple of years ago and also an 8lb jug of H4350 and I have been set. I guess I am out of the loop!

 

[South Pender]

Very interesting, LolaPP. I've been researching .270 Win. powders. According to QuickLOAD, the max load given on the Hodgdon reloading website of 54.7 gr. of StaBALL 6.5 should give about 2900 fps. from a 24-inch barrel. Pressure would be about 61,300 PSI. That from unfired or FL-resized brass (capacity about 67.5 gr. water to the top of the neck). So maybe not the highest velocity for that bullet, but, from your own shooting, a very accurate load. The burn rate is right beside Hodgdon 100V, Vihtavuori N550, and Alliant Re19, so about where you'd expect a .270 Win. powder to be. A slightly slower burning powder would probably give higher velocities--the champ right now, according to QuickLOAD, in that regard being Alliant Re26.

As for barrel life, the size of the powder charge is relevant, but not in a really-significant way. Here's a useful barrel-life calculator using an Excel spreadsheet program. When I enter the relevant data for this powder and bullet (54.7-gr. powder, 140-gr. bullet, 61,300 PSI), I get about 2082 rounds of accurate barrel life, allowing at least a minute between shots (allowing 2 or 3 minutes between shots doesn't change this result). I used the value of 3600 kJ/kg. for powder heat for this powder--the value given by QL. Powder heat for many powders is given in this calculator, but not for Winchester StaBALL 6.5. Using powders with higher powder heat will reduce the accurate barrel life.

http://bulletin.accurateshooter.com/2008/10/spreadsheet-formula-calculates-useful-barrel-life/

 

[cbh560]

That's the point - factory data shows those numbers with a low 57,900 PSI (SAAMI max is 61,000 PSI). Or 162 A-Max at 2821 fps and 59,000 PSI.

Like I said, almost sounds too good to be true.

Mark - picked up 6 pounds of RL26 from you guys a couple of years ago and also an 8lb jug of H4350 and I have been set. I guess I am out of the loop!

When I input those parameters - 7-08, 150 ttsx, staball 6.5, and book values for seating depths, etc.- without any tweaks in GRT, I am getting a pressure 77K PSI for a muzzle velocity of 2900 fps at 48.2gr of powder and 109% case capacity. Obviously that is way over Hodgdon's pressure for those same velocities. Curious though....all the same parameters with a different bullet type (ex, Sierra 150 SPBT) is showing a velocity of 2750 fps, 100% case fill, and 58K PSI.

I'm not sure why the dramatic differences other than the long bullet construction of the TTSX. I have never reloaded monolithic bullets myself, so I don't know the nuances of them.

 

[todbartell]

monometals are much longer for their weight, that will effect pressures as the bearing surface alone is much greater. Then you have how much capacity the seated bullet occupies, etc come into play

 

[LolaPP]

Thanks for that - all sounds about right to me. I haven't run it over a chrono yet but it'll be just under 3000 fps. That's fine for me, I don't see any benefit in chasing another .03% or in velocity, nor the need to keep another powder on hand just for .270 Win. The attraction of SB 6.5 for me is it's performance in a wide variety of cartridges.

I think the barrel life figure is quite low, but I guess it all depends on what's considered acceptable accuracy. I think too that waiting a minute between shots is a bit excessive - I'm not inclined to spend five minutes to shoot a single group. As long as you don't get the barrel cooking hot, you'll be fine. If you think about it, it doesn't even really make much sense to make it a time vs temp based thing - if you're shooting in Arizona in the summer, you'll start off with a barrel already far hotter than if you fired five rounds in Iqaluit in February...

Very interesting, LolaPP. I've been researching .270 Win. powders. According to QuickLOAD, the max load given on the Hodgdon reloading website of 54.7 gr. of StaBALL 6.5 should give about 2900 fps. from a 24-inch barrel. Pressure would be about 61,300 PSI. That from unfired or FL-resized brass (capacity about 67.5 gr. water to the top of the neck). So maybe not the highest velocity for that bullet, but, from your own shooting, a very accurate load. The burn rate is right beside Hodgdon 100V, Vihtavuori N550, and Alliant Re19, so about where you'd expect a .270 Win. powder to be. A slightly slower burning powder would probably give higher velocities--the champ right now, according to QuickLOAD, in that regard being Alliant Re26.

As for barrel life, the size of the powder charge is relevant, but not in a really-significant way. Here's a useful barrel-life calculator using an Excel spreadsheet program. When I enter the relevant data for this powder and bullet (54.7-gr. powder, 140-gr. bullet, 61,300 PSI), I get about 2082 rounds of accurate barrel life, allowing at least a minute between shots (allowing 2 or 3 minutes between shots doesn't change this result). I used the value of 3600 kJ/kg. for powder heat for this powder--the value given by QL. Powder heat for many powders is given in this calculator, but not for Winchester StaBALL 6.5. Using powders with higher powder heat will reduce the accurate barrel life.

http://bulletin.accurateshooter.com/2008/10/spreadsheet-formula-calculates-useful-barrel-life/