6MM / .243 100GR HORNADY BTSP load development

[TOP PREDATOR]

My go to load for the .243 are Hornady 105 BTHP, followed by the Amax, Using 46.5 gr of H-1000 .005 off the lands of the Rem 700 heavy barrel 26" Varmint. Anyone that is looking for these bullets knows they are quite hard to come across these days. And thanks to all here at the Hide that helped me along with this load. http://www.snipershide.com/shooting...-depot/203140-hornady-243-105-grain-bthp.html

I remembered my first box of rounds through that rifle using factory Hornady 100 BTSP just to season the barrel performed really well at 100Y, but ran out of those shells to run them out further.



I found a few boxes and ordered them, then loaded them at 46.5gr (same as the 105's) and at 46gr. I also played with the seating depth along the way. The goal was to find a steel plinking substitute until the BTHPs or Amaxes come back into circulation, without being too far off from my go to load with powder or dope. Shooting 5 rnd groups @ 200Y I've found the 100gr BTSPs are only .75" lower POI away from the 105's POA at that distance.

Granted there is at least another range trip or two before I settle on a final pacifier load, including trying 44.5, 45, 45.5 grains of H-1000 and the final seating depth. The 105 BTHP I was running clocked in at 2809 FPS, perhaps a grain less will equal things out a bit, and hopefully a somewhat equal ground can be reached with the lower BC and weighted BTSP. Just an armchair guess.

Some numbers on the 100gr BTSP factory Hornady load: .405 BC, 2.630 OAL, 2.040 case trim length, 43.2gr of __?__ (some sort of flake powder), 3,046 fps.

My 105 BTHP load: .530 BC, 2.780 OAL (.005 off lands), 2.040 case trim length, fed 210 primer, 46.5 gr H-1000, 2809 fps

Some numbers on the 100gr BTSP reloads (FPS avg of 5 rounds through a chrony, 200Y, 36 deg F, 41% hum, 2:00 to 10:00 5-7mph wind, using a 1.5" round spot, bipod and rear bag) that I have so far:

(OAL set at 2.708 was against the lands)

46 gr H-1000

2.703 OAL -.005 from lands 2848fps 1 7/8" x 5/8" CTC group (minus the known pull shown)

2.698 OAL -.010 from lands 2827fps 1 1/8" x 7/8" CTC group



46.5gr H-1000

2.703 OAL -.005 from lands 2857fps 1" x .5" CTC group (minus the known pull shown)

2.698 OAL -.010 from lands 2860fps 1 3/8" x 5" CTC group

2.693 OAL -.015 from lands 2855fps 1 7/8" x 5" CTC group (I aimed at the wrong spot the 2:00 hit was to be the first shot on the spot to right)

2.688 OAL -.020 from lands 2905fps 1 7/8" x 1.5" CTC group




At both charges, the 2.703 OAL seemed to have more of a left to right thing going on rather than vertical stringing, will have to reshoot them (it may have been me or a coincidental windier condition while shooting them). If it was just me or the wind, and that Left and right thing goes away, that'll be a killer load / seating depth vertically stringing only a .5" at 200Y!

I didn't think it too bad considering the first time out with this bullet, and a SP on top of it. And only a .75" deviation from my go to load at a 200Y zero. More too as I tweak the load more, settle on a charge seating depth, and to get some data at different distances.

The avg length of the 100 BTSP's is 1.069, the A max 105's is 1.244, and the 105 BTHP's is 1.223, so the shorter & lighter 100's may give good performance for those that have twists that are having a tough time doing the heavier longer bullets. They weren't too far off of the more regarded premium 105 BTHP & Amax bullets at the same charge, and are of a hunting bullet construction too.

 

[No1]

243 win
RL22
42.5g
100g Hornady BTSP

I fooled around with some other bullets at first but settled on these. I just use my 243 for hunting though.

I bet that "flake powder" in the factory ammo was a flattened ball powder.

 

[TOP PREDATOR]

^ have no clue what it is, but worked really well at 100Y

03/07/2014 UPDATE ON THE LOAD DEVELOPMENT:

OK, I did something semi silly, I figured the lighter weight by 5 grains on the BTSP may "compensate" for drop by doing a lighter charge in the case. Perhaps I should have ran a calculator first, I'm taking it as the lower BC of the 100gr BTSP means that I had to "up" the charge somewhere to 2900FPS. In "virtual land", looks like the BTSP would be practically identical to the BTHP out to 400Y.



So yesterday's range trip was just blowing powder and eating components, but got some useful "lower recoil" data and seating depth using H-1000 and a hunting constructed bullet:

45gr 2.703 OAL 2707 fps
45.5gr 2.698 OAL 2756 fps
46gr 2.693 OAL 2798 fps



Back to the drawing board, next step is H-1000:

46.5 gr 2.688 OAL got me to 2900 ish before, so that gets me to the FPS the calculators say I need to mimic 105 BTHP match (to 400Y)

Will have to try:
47.0 gr 2.703 OAL
47.0 GR 2.698 OAL

Once they are whipped up, will confirm 200Y POI "zero" of the 100BTSP vs 105BTHP, and compare the POI from 100 - 400 yards.

Remember, not looking for screaming loads here, just a "substitute" for short to mid range distances for the 105 BTHP's using the same powder and optic settings.

 

[TOP PREDATOR]

UPDATE 05/16/2014

Finally the winter had gone away, but still had to contend with some wind 5-12 mph, 10:00 to 2:00. In spite of that, headed to the range, 71 Deg F, 71% hum. Shot 5 round groups with each 100 BTSP load and seating depth at 100 & 200Y along with a group at each distance with the 105 BTHP to use for a POI comparison. I think the wind opened them up a little as the 105 BTHP groups were a little more open than history shows what they are capable of.

Used and did not adjust my 200Y zero turret setting with all loads, bullets, and distances to get a good idea of any POI differences and drop data.

VELOCITIES (don't know why, but the FPS went DOWN with the deeper seating. Seems the more the case capacity was reduced, the velocity was reduced? Always seen or expected velocities / pressures go up when deeper seated with the same powder charge. This one has me scratching my head.)

47gr 2.703 OAL 2930 FPS
47gr 2.698 OAL 2907 FPS
47gr 2.693 OAL 2882 FPS
46.5gr 2.688 OAL 2933 FPS

Results of the 100gr BTSP using H-1000 @ 200Y:

47gr 2.703 OAL 2" Group 1" higher than 105 BTHP POI
47gr 2.698 OAL 1.3" Group .25" higher than 105 BTHP POI
47gr 2.693 OAL 1.3" Group .5" lower than 105 BTHP POI
46.5gr 2.688 OAL 1.8" Group 1" lower than 105 BTHP POI

Results of the 100gr BTSP using H-1000 @ 100Y:

47gr 2.703 OAL .86" Group 1.5" higher than 105 BTHP POI
47gr 2.698 OAL .81" Group .25" higher than 105 BTHP POI
47gr 2.693 OAL 1.02" Group .25" lower than 105 BTHP POI
46.5gr 2.688 OAL .59" Group .5" lower than 105 BTHP POI

For a lead tipped hunting bullet design the 100gr BTSP performed rather well vs. the match bullets, not that far off from the 105 BTHP at 100 & 200Y group size or POI, especially with the 47gr of H-1000 at 2.698 OAL (.010 off of where the ogive rested againts the lands in my Rem 700) @ 2907 FPS load. The additional 100 FPS with the 100 grainers seemed be the equalizer at these 2 shorter distances, without having a drastic change to optic settings to compensate for using the different head. POI at both distances is just within .25" higher, with the amount of drop being the same between the two distances. No differences in windage.

The next few weeks I'll have access to shoot 300 & 425Y, and hopefully will be able to see how they compare a little further out, but am confident that they will be just as effective as the 105 BTHP / Amaxes out to 450Y as the Ballistic calculators suggest, and also will double as a VERY accurate hunting bullet.

 

[TOP PREDATOR]

Finally got to try the 100 gr BTSP at further ranges yesterday. Good news for the 6MM Hornady users that have a small reserve of the more premium bullets, or having a difficult time finding 105 BTHP Match / Amax during the “suspension of production”.

To recap the load:

Hornady 100 gr BTSP
47 gr H-1000
Fed 210 LR primer
brass trimmed 2.040
OAL 2.698 (.010 from lands, Rem 700 1:9.125 twist)
2907 FPS, 26" barrel, chrony 10' from muzzle

Shot prone, bipod and rear bag

100Y .81" CTC 5 shot group
200Y 1.3" CTC 5 shot group
325Y 2.25" CTC 5 shot group
425Y just under 4" CTC 5 shot group

In comparison to 105 BTHP load:

46.5 gr H-1000
Fed 210 LR primer
Brass trimmed 2.040
OAL 2.780 (.005 from lands, Rem 700 1:9.25 twist)
2809 FPS, 26" barrel, chrony 10' from muzzle

100Y .7" CTC 5 shot group (46 gr printed a .81, same as the BTSP)
200Y 1.75" CTC 5 shot group
325Y 2.50" CTC 5 shot group
425Y 3" CTC 5 shot group

At all distances up to 425Y, it appears the 100 BTSP very closely matches within .25” to .75" the performance (drop, POI, POA) of the 105 BTHP Match, and after looking at some more notes, the 105 Amaxes too when the 100 BTSP are pushed 100 FPS faster, and seated back just a little deeper. As far as printing on paper, it is one hell of an accurate hunting bullet out to 425Y - with no real adjustments needed to zeroes, optics, holds or other DOPE.

So even for a less glamorous bullet, it appears the humble 100 gr BTSP is one heck of a bullet, either as a substitute for the more premium heads out to 425Y or standing by itself as "the bullet that could", with better availability than the 105 BTHP & Amax that can be used at shorter to "mid" distances before the higher BCs of the "premiees" starts to be of value.

 

[Fuzzball]

#4: "VELOCITIES (don't know why, but the FPS went DOWN with the deeper seating. Seems the more the case capacity was reduced, the velocity was reduced? Always seen or expected velocities / pressures go up when deeper seated with the same powder charge. This one has me scratching my head."

Don't scratch too hard, that's perfectly normal in rifle loads. Your loading data makes it seem you're varying charge weight and seating depth at the same time; if that's so, you don't have a clue what's causing anything.