Home Forums Reloading Reloading Software Would like Quickload IMR8208 data

For the load you specified the barrel time is .848ms.

25gr even gets you .858ms.

Thanks for that. Will check it out.

I presume the next node up would be over pressure. A quick guesstimate says around 26.4gr, eh?

Not over pressure but you're getting to nearly 108% fill.
26.5 is .787ms 26.6 is .783ms.

At 25.2 grains i can still hear a little bit a powder shake, so that's not yet at 100% capacity. How much can you compress in these small cases?

Also, at what psi is considered over pressure?

SAAMI MAP is 55,000

CIP MAP is 62,366

I've been using CIP.

I don't know about the compression question in the .223 case.

Can this data be extropopated to get velocity / pressure of OBT from other powders? Mainly interested in IMR 4895 data.

I'd be looking at H335 or Ramshot X-terminator.

Much higher velocities and much less compression.

This is being used in extreme conditions. Coyote calling, 25F Below in winter, and up to 70F Above in fall for deer. Am using only 1 load for all. That's main reason i'm using imr 8208, has very little fluctuation. I'm open to other powders, but has to be an Extreme powder.

With 50-grain bullets _in general_ I've had good results with IMR4198. The 4198s (Hodgy-branded and IMR-branded) are both advertized by Hodgy to be extremely temperature stable. At this point, they're both Thales powders out of Australia, but I don't believe data is interchangeable. I don't shoot Barnes bullets, however, so I don't have experience with that specific combination.

Back from the range. Don't look very good. 25gr 8208, OAL 2.185.

Velocity: 3054, 3063, 3097, 3037 (avg 3062fps). Was a 2.25" group.

I know this rifle is capable of doing much better (it consistantly shoots 1/2 groups with 40gr Bergers). I think I may have a stabilizing problem with these Barnes loads (barrel is 1/12 twist). What do you guys think?

I'm using a faily thick plastic walled pail as backing for my target. I haven't noticed elongated holes, but what I have noticed is that the bullet tips are buried in the plastic beside the exit hole.

So how does one find out if the bullet stabilizes? Would shooting at 200yds tell me more? Also, would cold weather compound the problem?

If you have marginal (or insufficient) stability, then everything that increases air pressure/density will make the issue worse, such as colder temps, lower elevation, or higher barometric pressure. Yes, taking them out to longer range will help you see whether they're stabilizing adequately or not.

Barnes' low-density bullets (any all-copper bullet is lower density than a lead-cored bullet) are longer per weight than a 'regular' bullet, and length is the primary factor in what twist rate you need for a given projectile. If you'd like to take precise measurements of the length of your exact bullets, you can plug that and the velocity into one of the calculators on the JBM Ballistics page and it'll calculate stability for you. IIRC, it just gives you a number. Whether that number is 'enough' is something you have to proof on-target.

Will have to give up with these. Another round with 3" groups. OAL 2.192, 25.5gr 8208 at 3162fps.

Quickload; What pressure and velocity #s do 21.1gr of IMR4198 at OAL 2.185" give?
Am also going to try some Benchmark.

48.5K and 3080.

What do you guys think of the primer on the left? It's from the 21.1gr IMR4198 load mentioned above. The casing on the right is from the above mentioned 25.5gr IMR8208 load.

Is that a cratered primer on the left? I hit my chrono with that round, so didn't get a reading (it'll still work though:). The right casing has a nicely flattened primer; the one on the left is still really rounded on the edges, but there is a crater around the firing pin hole. It's visible, and the ridge gets your fingernail caught when sliding over it.

Am wondering if it tells me anything.

[img]http://pbckt.com/pE.OlbzP5[/img]

[img]http://pbckt.com/pE.OlbahN[/img]

Cartridge on the left saw less pressure than the one on the right, IMO.

Agreed.

Benchmark is next. What numbers do 25.6gr at OAL 2.205 give?

Gonna give these bullets one last shot with this combo.