Nosler 64gr BSB and IMR 8208 XBR- Need advice please

[IdahoG36]

A few months back, I purchased three 250 count boxes of Nosler 64gr bonded solid base .22 bullets. I have 16lbs of IMR 8208 XBR on hand, and use it for all of my .223 reloads. I looked all over and could not find load data for this combo, so I contacted Nosler. They stated to use Hogdon's data for the 63gr Sierra SP bullet.

Hogdon shows a starting load of 21gr, and max of 23.1gr @ 52,400 psi. The Sierra is loaded to 2.220" COL, and Nosler specifies 2.175" COL for the 64gr BSB. So I started at 21gr and worked up to 23.0 gr in .2gr increments, with a COL of 2.175". I had no signs of pressure at all with any of the rounds, so I went ahead and loaded 120 of them; enough to fill 4 AR magazines.

I purchased a chronograph a few weeks ago, and ran some of these rounds to see where I was velocity wise.Temp was 81*F, humidity 10%. Five shot average from 10 feet was 2450fps, ES-90, SD-37.

These were shot out of my 14.5" POF P415 Gen 3. I know that with a shorter barrel, there would be some velocity lost. But 2450fps is too low for my taste, and the ES is way too much. The ES on my 55gr plinking rounds is 30.

I wanted to see if anybody is using this combo, and what you are loading yours to. My load data is as follows- 64gr Nosler BSB, 23gr IMR 8208 XBR, CCI 400, once fired LC brass, COL 2.175".

I am thinking of continuing upwards on the powder charge to 23.6gr in .2gr increments, and if no signs of pressure, perhaps continue to 24gr max; again in .2gr increments. Before doing that though, I thought I'd ask here and see what others are loading to safely. If I can get 2650 fps from 10 feet, I'd be ok with that with a 14.5" barrel. If not, I may have to go buy a couple pounds of CFE 223 instead.

 

[Unclenick]

With a 14.5" barrel, you can expect about 350 fps less velocity than the 24" standard test barrel length achieves. That's just the physics of the short barrel and there's nothing you can do about that except pray to God that he change the laws of physics for you. However, you should be closer to 2550 fps with that load if all else were equal, which it seldom is.

You probably have a longer freebore and wider 5.56 chamber rather than a .223 Chamber. That will cost you velocity. You should measure at 15 ft from the muzzle (the SAAMI standard) for comparable information to Hodgdon's; it also avoids false triggering problems. Your larger chamber probably means you are running at lower pressure than Hodgdon lists for the same load. The large ES indicates inconsistent ignition. I would use a magnum primer like the CCI #41 to increase the start pressure. I would be very careful about seating the primers to ensure they are seated at least 0.002" and as much as 0.006" deeper than when you feel the anvil fit touch the bottom of the primer pocket. This is necessary to pre-load the priming mix contact between the cup and anvil for most consistent ignition. It is called "setting the bridge" in commercial lingo, and "reconsolidation of the primer" in military lingo.

Read this article.

 

[Tomas]

I dont know that CFE223 is going to help at all. Since it is so much slower than 8208, I think you may find your velocities decrease even further in that short of a barrel. If anything, go with a faster powder like 335 or even 322.

I'd also try the #41s, CCI 250s or even BR primers, all of which are hotter.

You could also try seating the bullet deeper, as this can have a profound effect on velocities. It's also a quick and easy experiment...no powder or primer change. Sounds like you are pretty aware of pitfalls, so go slow, as pressures will increase.

I'd try deeper seating first, then the hotter primers, before I'd go out and get new powder. You have a lot of the 8208, may as well work all your other options before you try a new powder.

 

[IdahoG36]

Thank you for the responses. I was thinking of trying the CFE 223 because the Nosler manual shows it was the most accurate load @ 26gr, and out of their test barrel was over 2900 fps.

What really concerned me was the ES when I chrono'd my rounds loaded at 23gr. That is obviously not a consistent shooting load. I am positive that all of my primers are seated uniformly, ever cartridge is 2.175" +/- .002", and the charges are 23gr +/- .1gr. All of my other .223 loads using 8208 XBR are very consistent accuracy and velocity wise.

.223 SAAMI max pressure is 55,000 psi; 5.56mm max pressure is 60,000 psi. At 23gr, I am guessing that I am around 50,000-51,000 psi of chamber pressure. 23.1gr book max shows 52,400 psi. I do have some room to go up, and still be safe. My POF P415 has a 5.56mm NATO chamber.

I have read that typically when going to a magnum primer, there will be an increase in pressure (obviously); but there is also an increase in velocity. Sometimes it can be a small gain, other times over 100 fps. I think that I will buy some CCI 450 SRM primers, download some test cartridges to 22.4gr, and work my way up in .2gr increments. I will load up to 23.6gr and see how they perform velocity wise, and watch for signs of excessive pressure.

It may be a week or two before I can get back out to shoot them, but I'll post an update.