Shot this group out of my 1-9 twist Model 12FCV
Norma Match .223 77gr SMK's
http://i228.photobucket.com/albums/e...MK%2012FCV.jpg
Printable View
Shot this group out of my 1-9 twist Model 12FCV
Norma Match .223 77gr SMK's
http://i228.photobucket.com/albums/e...MK%2012FCV.jpg
Very nice, I have a 12 BVSS in .223 that I love.
Mine is doing just under 1 inch at 100yds but I don't quite have the perfect load.
55gr v-max and 24.1gr of IMR4895, I also tried 8208XBR with good success.
Don't discount something heavier. Mine seems to handle the heavier much better than the lighter ones. You may spend a lot of time and powder on 55's, when something heavier will fill the bill.Quote:
Originally Posted by HalfTrack
AR COMP 25.5 gr 50 v max 1 3/4" @ 400 yards today
Hi WV, I completely agree with you. I have a bunch of the v-max left, not too available when I got this project going.
I am going to try the SMK's and I think some of the ?ELDX? from Hornady soon.
Thanks for the feedback..
FWIW - This is the answer that I have been led to
"the "accepted" standards for what twist is needed for what bullet are, for better or worse, thought of in relation to the standard 20" AR-15 barrel. Because your barrel is 26" long, you are probably getting close to 150 fps higher speed than the box states, about 190 fps faster than most AR-15 loads, and it's pretty **** hot loaded anyway. What that means is that you are likely doing a fair amount higher RPM than the "accepted standard", which generates an increase in axial rigidity; thus, the bullet shoots."
Your 77 MK measures .994 long. Plug that into the Berger twist rate calculator http://www.bergerbullets.com/twist-rate-calculator/ and see what your stability index is. Below 1.5 is marginal.
My 9 twist BVSS in 223 would not shoot the 75 hornaday BTHP except with a hot load on a 100 plus degree day.
My 8 twist Criterion barrel shoots the 75 hornadays and 77 SMK and TMK very well.
On some much earlier post on the subject, I seem to remember that a bullet spinning at about 95% of its rated RPM was stabilized best. For Hornadays that 95% of 280,000 RPM. Sierra's are rated at 330,000. If I'm wrong on that, perhaps some one will provide the correct information.
Velocity times 720 divided by twist (9 in your case) = RPM.
I hope this helps.
I just picked up a 12FCV last week and had a little apprehension during the purchase because of it being a 1/9 twist. Reason is I have a boatload of 69 and 77 grain sierra bullets that I use in my varmint AR loaded with Ramshot Tac. Surprisingly both loads grouped well under an inch in the Savage which I'm sure is attributed to the 26" barrel helping achieve higher velocities. Now I just have to find the time to fine tune them and see what this rifle can really do.
Thanks it helps a lot.Quote:
Originally Posted by Texas10
It gave me a stability factor of 1.77
I need to check the rate of twist.
I shot some 55gr. on Sunday that patterned like a precision shotgun.
If you're wanting some cheap thrills, try some American Eagle 50 grain tipped varmint ammo. Part number is AE223GTV.
These shoot under a minute all day long, although I have many targets with 3 shot ragged holes at 100 yds. I've chrono'd them at 3340 to 3380 fps out of a 26 in barrel, and hit 9 inch steel at 500 yds consistently with these.
You won't find them on Federal's website, nor does the box provide much info. I had to email Federal to get the spec sheet.
I've found them for as little as $5.88 a box online, but cheapest lately seems to be about $9.98. Brass is great for reloading.
Great ammo to warm up with before shooting your expensive stuff, but it may leave you shaking your head as to why you paid a lot more for the other stuff.
Thanks for the tip!Quote:
Originally Posted by Texas10
I found a bunch on ammoseek
I couldn't find it on Ammoseek, but did find some here. https://www.ammunitiondepot.com/593-...grain-bpt.html
Maybe I have to join ammoseek to be able to search by part number.
Oops, gone!
https://www.slickguns.com/search/apa...rms_wikiarms=0
http://www.munireusa.com/federal-standard-223-remington-5-56-nato-v-max-50-gr-20-rounds/
https://www.natchezss.com/federal-am...ion-69628.html
http://www.sunfloweroutdoorsports.co...categoryId=197
http://www.wholesalehunter.com/produ...&source=A10003
https://www.woodburyoutfitters.com/f...e-223rem-13267
https://www.budsgunshop.com/catalog/...ducts_id/82535
Apparently this is Hornady V-Max
https://youtu.be/ycgVDkQ6ZL8
Freedom Munitions has a few different loads
https://www.freedommunitions.com/amm...rand=hornady-r
Yes, according to the spec sheet I got from Federal, it is a V-Max. I have weighed and measured the bullets and found them to be identical to V-Max except for the color of the tip plastic. I even performed something of a melt test to see if they had a higher temp plastic, possible precursor to the ELD tips we see now. But I found them to be pretty much identical to current V-Max.
Typically, I find supplies of this ammo dry up about this time of year. I suspect that Federal estimates their market for the following year around Christmas time and makes a run in the late winter. Supplies start arriving at stores in early spring, and I pick up a few boxes to see how the new lot shoots.
This years batch is shooting much better than last years and is identified by two "dots" on either side of the "FC" embossing on the head. Brass consistency is much better and flash holes are mostly centered, as compared to last years run where flash holes were mostly off center, sometimes by a wide margin.
Remember about the stability calculators...
They are for an idea, not for a fact; since they are all based upon the Greenhill formula.
The trouble with absolutes is a few fold.
1) The atmospherics will play into this, help/hurt/whatever.
2) Actual twist rates. This is a 2-part issue. It is not uncommon for the ACTUAL twist rate to vary from what is stated by about half-a-twist. The other part of this, is the barrel smoothness itself. A barrel that doesn't grab the bullet as efficently can do some funny things. If the bullet "slips" or skids for a bit the observed twist rate will be different, and anytime jacket damage happens you can get some other factors.
3) Velocities. Remember there is no "X" fps gain or loss with a given barrel length. Far too often this gets very exaggerated, especially with factory ammo. If a factory can save a few % of a penny on a different powder, better believe they will. So that powders burning rate in a different barrel may or may not mean a practical difference. I'm not convinced it's in a companies best interest(selling a sexy velocity number) to constantly update a box or a website to reflect what you are actually shooting.
I've had a few 9-twist Savages that shot the 77gr SMK's very well to 1,200 down on the boarder, but weren't so stelar up here.
Yes! Thank You!
I'm putting my trust, and money, into 69gr SMK's. I have some 69gr TMK's on the way as well
I have a 1-7 AR that I have the 77gr. SMK's for.
You aren't talking about light varmint bullets, but for another bit of info to make your head swirl :cool:
Some years back, I called the domestics and asked about RPM limits before they start to come apart.
Of the bullets discussed so far, ROUGHLY(back to barrel smoothness) the RPM limits are going to be 290,000 - 320,000 RPM.
MV * 720 / twsit = RPM
Other than the occasional coyote hunt this rifle is mostly going to be used as a centerfire trainer for my Model 12LRP 6.5 Creedmoor match rifle.Quote:
Originally Posted by darkker
Quote:
but for another bit of info to make your head swirl :cool:
Some years back, I called the domestics and asked about RPM limits before they start to come apart.
Of the bullets discussed so far, ROUGHLY(back to barrel smoothness) the RPM limits are going to be 290,000 - 320,000 RPM.
MV * 720 / twsit = RPM
LOL! I'm getting about 226.000 RPM with the 69gr. It's getting colder