About FPS

[chetc]

i am loading 75gr Amax, 205 primer, 24.5 Varget, shooting this load out of my new model 12 fv in 223 with a 9 twist, curious about approx what fps am i getting.

Chet

[Zero333]

2,950 - 3,000 fps is my guess if it's a 26" stick they're flying out of.

Ran the #'s in Quickload and with a coal of 2.300", 24.5gr of Varget come up as making 69,000 psi ! at 3,035 fps.

I assume you're not over pressure like QL suggests (hence why to always work a load in your rifle and not copy others), so I lowered the charge weight to 23.8gr which shows as making 62,000 psi and 2,950 fps.

[The Old Coach]

I get about the same numbers as Zero333. Hot load. Watch your primers and other pressure signs.

[WV1951]

Will 75 gr. not be borderline too big?

[bigedp51]

Throat length will play a big part in Quickload chamber pressures, my Savage .223 with a 1 in 9 twist has a longer throat than my AR-15 rifles do and can be loaded warmer.

Look at line G freebore diameter and line N below at freebore length below




HOLLIGER ON .223/5.56 CHAMBERS
http://www.radomski.us/njhp/cart_tech.htm

Also Quickload defaults to 28 grains of H2O case capacity when most cases have a capacity of over 30 grains of H2O case capacity. This difference in case capacity can change the chamber pressure 6,000 psi.

[Zero333]

Great info bigedp51.

Thanks !

[Fat Albert]

If you can go out and get a $1200 rifle than you should be able to get you own copy of QL. Here is their site http://www.neconos.com/details3.htm

[The Old Coach]

I've never found anything in QL that takes throat length into account. Seating depth, yes, but not throat length.

[chetc]

update!! was out shooting tonight, ad out of 15 shots with my 223 load, 75 Amax, fed 205 primer, 24.5 varget, i had 3 primers pierced and some smoke came out of the blow by hole on the side of the action and hard extraction, i have a shoot this weekend and i am not going to be able to get out to try any changes i make in the load, as one user mentioned above about trying 23.8grs, will this load make a difference to load up 50 and enter the shoot, NOTE: this load has worked for the last 2 weeks around 50 rounds with no issues, does primer seating have any effect here. i am loading .010 off the lands

Chet

[Robinhood]

Better than blowing holes in your primers. You were warned in post #2 and 3. Clean your bolt real good because of the gas that cut into your bolt head and firing pin.

[Texas10]

Just loaded a 75 amax and Varget work up in half grain increments this morning. First time in my Criterion 26 in, match chamber, 8 twist. Hoping the 8 twist will stabilize the 75's as well as it does the 69 grain Tipped match kings!

Anyhoo, I am seating .010 off lands at a base to OGIVE (BTOG) of 1.945 which makes the COL 2.486

Hornaday manual lists loads from Service Rifle Data starting at 19.4 grains @2200 fps up to a max of 23.5 @2600 fps, and a COL of 2.390

Lee manual list loads starting at 22.5 grains @2693 fps. up to max 25.0 grains @ 2907 fps. and a COL of 2.250.

And...I see you've just updated your information. Blowing primers, could be excessive pressure, maybe temps got hotter? But in my son's 12 FV, he was blanking primers at low pressures. Turned out to be a firing pin fit issue. Too much clearance in head. How much work have you done to the bolt and firing pin to improve fit and function?

Could also be you're seating the bullet too far into the case to make chamber fit and pressures are a bit higher than book. Got more data to share? What's your COL, and more importantly what is your BTOG, and how did you determine it? Perhaps you were into the lands and pressures spiked.

[Texas10]

And...you might also check your overall case length. Are you trimming your cases. Do you FL size? or just neck size? If your cases stretched beyond max length, you could be pinching the bullets and spiking pressures too.

Maybe if you tell us about your reloading procedures, the answer will become more clear.

[chetc]

full sizing, cases trimmed, shoulder bumped back .003, , not sure what BTOG means, i keep the oal very close i seat with a seater with a dial indicator, most groups are well under 1/2" one was in the 1's. i can neck size, but i don't, but can give it a shot, i do neck size in my 6.5x284 with a brux barrel heavy gun.

Chet

[Texas10]

On my 12FV and my 12BVSS I've never had to FL size or bump the shoulder, even after a dozen cycles. Only neck size and occasionally anneal. But in my new 12FV in 22-250, I do have to bump the shoulder every second loading. Grows about .001 and headspace is very tight.

BTOG, see post 11 above. How are you measuring your distance to lands? When my 12 FV's were new, I grabbed a bunch of bullets I might use and measured and recorded BTOG before shooting for the first time. Then after barrel break in , measured again and recorded change.

Measuring OAL is unreliable as meplat is inconsistent. If you're going to seat to a particular depth with a micrometer equipped seating die, it helps to be able to measure your BTOG reliably.

You may need to do a full load development before expecting this load to perform to competition levels. OCW followed by seating depth tune, and final charge tune. See http://www.bergerbullets.com/wp-cont...13/03/COAL.pdf

But you may find, as I did in my 12 BVSS that the 75 Amax will not stabilize well enough in a 9 twist, except at very high density altitudes, or at pressures and velocities that are way past your safe operating zone. Check the Berger twist rate calculator, and plug in your data. http://www.bergerbullets.com/twist-rate-calculator/

IF you can't get that bullet to stabilize reliably in your 9 twist, try the 69 grain Tipped Match King. Excellent BC, and well stabilized in my 8 twist at 3120 fps. Also try the 73 grain Berger, although that one was marginally stable in my 9 twist unless I really cranked up the velocity. Then it becomes a real barrel burner.

[chetc]

hi Texas10
i don't have any problems stabilizing in either of my 3 223's, i have the 12 bvss shoots 25 varget 75 Amax with never any pressure issues, even in 90 plus weather with plenty of groundhog kills out to 711yds, i really like the bullet, going to try the 23.8 load and go with that for the shoot on sat, my buddy has the Rem PSS in 223 he shoot the same bullet with 24 tac and no issues, also my gun likes the sierra 52gr #1410 with the IMR 8208 XBR, shoots tight, but don't know if i want to try that bullet this weekend, we will be shooting out to 430yds, i am thinking the 75 will be the better choice. any comments on the bullet choice there.

chet

[Texas10]

In my 9 twist I found the Hornaday 75 grain HPBT shot tiny groups as long as the temps were near 100F. But as soon as fall arrived and temps dropped, it wouldn't group worth a darn. I fell back to the 69 SMK and 8208 for a killer load out to 750 yds. Then I found the Tipped Matchkings. They shoot flat as a pancake with 25.9 Varget and going 3140 fps. Can't wait to try them out to 1000. Should be doing 2000 fps + at 1000 according to Hornaday Ballistics calc.

The 53 grain V-Max has a pretty good BC . I shoot it over 3031. The sierra 1400 HP shoots well over 8208, both in my 12FV, with groups mostly under .300 and sometimes in the zero's.

I'd take the "known to be good" 52 over the problematic 75, at least until you can figure out what's going on and get a consistent load working. I've shot a 50 gr American Eagle load well past 500 yds. so your 52 grain starting at 3300+ should not have a problem getting there, on target, crosswinds aside.

[chetc]

hey texas10

good info there, i am new with IMR 8208 XBR, and i do happen to have the new sierra 69 TMK, about what charge are you shooting, never tried the 53vmax either, going to load up
my sierra 1410 bullets later with the 8208 XBR and see how it shoots

Chet

[m12lrs]

Try CFE223

[BillPa]

In my 9 twist I found the Hornaday 75 grain HPBT shot tiny groups as long as the temps were near 100F. But as soon as fall arrived and temps dropped, it wouldn't group worth a darn.

You may want to take a look at the Enduron powders. Late last fall I was playing around with 4451 in my 260 but time ran short to do any real work with it so I used my old load w/H4350 for goat chase'n. Last week I picked up a pound each of 4166, 4955 and another pound of 4451 to play with in a few other cartridges. Hopefully I can use the 4955 in the 25-06, 280 and 280Imp and get away from R19-22.

A few temp sensitivity tests...
http://www.chuckhawks.com/imr_enduron_powders.html
http://bulletin.accurateshooter.com/...-new-imr-4451/

Bill

[chetc]

well i went to the local shoot, distances were 200.300 and 426 yds, i took the 52 gr sierra #1410 I cleaned the 2 and 300 yd targets. as did my buddy with his model 700 heavy barrel in 223 shooting the 75 Amax bullets. at the 426yd line i was shooting the sierra 52 hp match 1410, the 52 sierra was not scoring well at that distance, luckily i loaded some 75 Amax bullets last tight, so i switched over to the 75 Amax loads, luckily they got me back in the run, there were 3 targets out there 8" dia, 5" and 3 "dia, i was shooting the 3" to get more points, going to stay with the heavier bullets for the next shoot, might try the Sierra 69tipped match kings, but the 75Amax is flat shooting was doing some excellent penetration on the steel, my buddy went 9 for 10 and i went 8 for 10 on the 3" dia. at 426yds. i just love the high BC on the Amax. so my buddy just for the heck of it shot 2 out of my gun with the Amax and he connected twice, it must be my eyes his eyes are about 13yrs younger LOL, but he is a good shot, so thats my story, gonna stick to it, young eyes work

Chet