Range Report: 300 SST & 1680 / CFE BLK

Talk about your 450b reloading experience, ask questions, etc...

Moderator: MudBug

Forum rules
Please try and keep it safe!

This information is the responsibility of the community, not the forum. 450bushmaster.net is not responsible if you blow yourselves up.

Range Report: 300 SST & 1680 / CFE BLK

Postby Hoot » Fri Jun 22, 2018 9:22 am

Said hey babe, take a walk on the mild side...

The more diverse our sources of 450b firearms become, the more I realize its getting hard to provide relevance in my experiments, that everyone here can benefit from. When the only game in town was the Bushmaster products, people could reproduce each other's results pretty reliably. My own perspective on what this platform could do was colored by my particular upper, with what I now know to have my oft referred to "loosey goosey" chamber. This was also influenced by my lack of experience with high power straight walled calibers. Heck it was influenced by as much misunderstanding as it was enlightenment. I guess that's why experimenting more, can just as easily create as many questions as answers. The point of this Midnight Confession is that coming into experiments with misinformation can lead to misunderstanding the results as often as having the those results dispel them. My brain keeps getting in the way of my fingers making any sense tonight, so Hear My Confession:

I have dabbled with AA1680 over the years in this caliber, using 300gr XTP Mags, Speer Gold Dots and Deep Curls and Hornady SST/ML bullets. Lately, I'm eating my words of the past in rediscovering performance where in that past life, I got unspectacular results. The turning point may well wind up being a change in brands of upper I use or it could be just dumb luck. I wanted to try something that few may benefit from, but scratches an itch I had this time around. IE an esoteric experiment. Using the 300 SST, I compare the difference if any, in performance between AA1680 and Hodgdon CFE Black, the latter of which I knew nothing about, save that it was rated similar to 1680, but with Hodgdon's Copper Fouling Eraser additive. Turns out they're more alike than different, well almost...

I began by seeing how much of each would fit into a case with one of those long 300 SST's seated to 2.27 inches. They look very similar in consistency, save a slight difference in color. For that task, I have a special case that I use, which has the primer pocket drilled all the way through. I seat the bullet in question and fill the case from the rear until the powder when settled, comes up to where the primer would usually end at the flash hole. Once done, I pour the powder into my weighing pan and see what I get, then pull the bullet and return the case to its safe keeping place, for future use. I was surprised to find that both powders at max fill, weigh within .2gr of each other and that is down near the margin of error using this charging method. They could well be identical, as far as I could reliably determine. Knowing that historically, 1680 ran painfully slow and after a quick check with QuickLoad, I decided to load the experimental steps starting with that max charge and down a few steps. I should clarify in case you haven't already noticed, I rarely find a 450b recipe that benefits from charge increments less than 1 grain. Mainly because the typical velocity SD's I get in this caliber are so high as a function of the limitations put upon the crimp, that within the same charge weight, the velocities vary by as much as I could calculate being due if there were a 1 grain change in charge plus or minus. Not at all like bottleneck calibers in that regard, but that's just life with the 450b.

My ability to compose sentences that are not mind numbing is not getting any better the more I write tonight, so Too be continued. 2 weeks later: Darn if I didn't forget all about this report. :|

Starting with 39gr and going up through the 42gr max charge, here's what I recorded, in spite of my temperamental LabRadar's best effort to thwart me. (I really need to get out more with it). I am slowly getting to know what not to do when setting it up. :roll:

Image

The orange results are a promised revisit to Lehigh Defense Xtreme Penetrators that I also did at the same range visit. I'll address them after I get done with the 300 SSTs.

As the results show, despite having the same packing density, the 1680 turned in velocities slightly higher than the CFE BLK, Not surprising as the CFE BLK is rated ever so slightly slower in the burn charts I saw online. I haven't had time to scope the bore to see if the CF really E's. ;)

On to the groups and I have to say, were much better than previous attempts to evaluate 1680 with the aforementioned bullets in the past. Hardly a group in excess of 1 MOA C-T-C.

So, here's what they produced, target wise:

First up is a revisit to the Brass, Lehigh Defense, Xtreme Penetrators.

Image

Not as Laser-Like as they did at higher, albeit worrisome velocities the last time out. Even at the high velocities the last time out, the Starline cases stopped just short of indicating critical pressure levels based upon casehead growth. So, if you're looking for single, jagged hole in a 1:24 system, think 2400 fps or more if you feel lucky punk. FWIW, the slower loads were still MOA C-T-C.

Now, on to the 300 SSTs over your grandma's powder. The targets show 4-shot 100yd groups instead of my usual 5-shot, to conserve available Starline brass that hadn't grown too much from the last time out.

These are arranged with competing powders side by side:

Image

I need to get better at remembering where I left the scope sighted in at, so that I don't keep losing an opening shot to a sighter.

Image

Image

Boy, the 41gr of CFE BLK sure did well but that's not my favorite pair of targets.

This is!

Image

:lol: I'm not normally a gambling man but when I called out the June Bug which had lit on my target, Mike Freeman, who was shooting his scoped .243 Model 70 next to me, took a look and as I was breaking the 2-stage, he said "Dollar on the shot!" Thanks goodness he didn't say that sooner as I'm a known choker and worse yet, I didn't have any money with me. Ruined what probably would have been a great group, but ruined that June Bug's day even more.

So, in conclusion: If you're not all caught up on the bleeding edge of velocity, the Hornady 300gr SST over either of those two powders will produce some pretty good groups and is pretty easy on the shoulder to boot. Image

Hoot

and Mike Freeman says, doot doo-doot doo-doot doot doo-doot doot doo-doot doot.... ;)

RIP Lou Reed 1942 - 2013
In Theory, there is no difference between theory and practice. In Practice, there is.
User avatar
Hoot
 
Posts: 3971
Joined: Tue Feb 09, 2010 9:34 am
Location: Minnesota

Re: Range Report: 300 SST & 1680 / CFE BLK

Postby cwlongshot » Fri Jun 22, 2018 12:16 pm

Thanks for posting HOOT!

I have two ladders with a 300g and AA!^*). I like the powder allot and use it in two calibers almost exclusively. The 357 Maximum and 22K Hornet. I just need to bring the 450 on one of the trips to the range!!

CW
cwlongshot
 
Posts: 41
Joined: Tue Apr 24, 2018 11:48 am

Re: Range Report: 300 SST & 1680 / CFE BLK

Postby Bmt85 » Fri Jun 22, 2018 10:24 pm

Another fine job, especially on the June bug! :lol:
You got some nice groups, and SD's! Kind of surprised you didn't get a little more velocity. Question for you, did you notice a point where you had a good amount of unburned powder on the lower end of your testing?
Bmt85
 
Posts: 352
Joined: Wed May 18, 2016 11:13 am
Location: S.E. Michigan

Re: Range Report: 300 SST & 1680 / CFE BLK

Postby Al in Mi » Fri Jun 22, 2018 10:30 pm

Wonder if that bullet expanded on that June bug :shock:

Good report hoot, when this jug of 1680 is done I planned to try CFE.
Al in Mi
 
Posts: 1189
Joined: Sat Jun 20, 2009 8:24 am

Re: Range Report: 300 SST & 1680 / CFE BLK

Postby Hoot » Sat Jun 23, 2018 6:07 am

Bmt85 wrote:Another fine job, especially on the June bug! :lol:
You got some nice groups, and SD's! Kind of surprised you didn't get a little more velocity. Question for you, did you notice a point where you had a good amount of unburned powder on the lower end of your testing?


Unfortunately, I didn't think to bring my white cover sheet with me to lay on the ground in front of my shooting station. Not using a conventional chrony, that also was not able to catch any ejecta. I'm sure there was some but didn't go out of my way to document it.

QuickLoad, in its typical fashion, predicted I would get more velocity than I did. Given its prediction of the amount of unburned powder and since I didn't get thoe predicted velocities, I'm sure I got even more unburned powder than it predicted I would:

QL predicts:

39gr 1680 = 88.4% burn
40gr 1680 = 89.7% burn
41gr 1680 = 90% burn
42gr 1680 = 92% burn

My actual velocities ran 150-200fps slower than QL predicted.

It figures that we have a Blue Jay Purdy Day breaking, 62 degrees and zero wind ad I'm at a loss for an experiment. I have things going on tomorrow and the range doesn't open until noon on Sundays out of respect for the neighbors, so today is go-time. I have some 200 FTX loaded up that I can evaluate to see how much Lil Gun has changed since I first bench marked them back in 2010, but that's about it. Even then, its a short ladder as I only had about 20 of them left. I may be able to load up some of those Copper, 250gr Lehigh Defense Xtreme Penetrators if I hustle it up this morning. That's all I have on hand that I haven't tested in recent years. Running out of cannon fodder and that can lead to taking a more active interest in other calibers, many of which I've been neglecting over the years, for the sake of the 450b.

Hoot
In Theory, there is no difference between theory and practice. In Practice, there is.
User avatar
Hoot
 
Posts: 3971
Joined: Tue Feb 09, 2010 9:34 am
Location: Minnesota

Re: Range Report: 300 SST & 1680 / CFE BLK

Postby Bmt85 » Sat Jun 23, 2018 5:18 pm

Well as long as you didn't see any unburned powder in the rifle, then I would think you're good. I know when I tried Shooter's World Blackout (similar to 1680 and CFE BLK) with the 275 TSX loaded long, I had unburned powder everywhere inside that rifle. I would have thought it would be similar with the 300gr jacketed you shot, maybe the diameter difference is enough to get those powders burning right.

Oh, I'm also liking those Lehigh numbers!
Bmt85
 
Posts: 352
Joined: Wed May 18, 2016 11:13 am
Location: S.E. Michigan


Return to Reloading for the 450b

Who is online

Users browsing this forum: No registered users and 7 guests