load development

[rohk]

ok, shot test loads today and with good chrono readings I can safely say 200's are the end of the lilgun effectiveness for my gun. never broke 2700, came close.

[Hoot]

ok, shot test loads today and with good chrono readings I can safely say 200's are the end of the lilgun effectiveness for my gun. never broke 2700, came close.

2700 is 3237 ft/lb of muzzle energy and a TKO factor of 512, which is incredible force. If they shoot accurate, that would be an excellent go-to load for all CXP2 and most, if not all CXP3 game.

Hoot

[wildcatter]

ok, shot test loads today and with good chrono readings I can safely say 200's are the end of the lilgun effectiveness for my gun. never broke 2700, came close.

2700 is 3237 ft/lb of muzzle energy and a TKO factor of .512, which is incredible force. If they shoot accurate, that would be an excellent go-to load for all CXP2 and most, if not all CXP3 game.

Hoot

Got that right, I ran the numbers and came out with significantly more TKO than a mag loading from a 250gr .338wm. TKO of 34.9 vs 32.6 for the 338wm..

..t

[Hoot]

ok, shot test loads today and with good chrono readings I can safely say 200's are the end of the lilgun effectiveness for my gun. never broke 2700, came close.

2700 is 3237 ft/lb of muzzle energy and a TKO factor of 512, which is incredible force. If they shoot accurate, that would be an excellent go-to load for all CXP2 and most, if not all CXP3 game.

Hoot

Got that right, I ran the numbers and came out with significantly more TKO than a mag loading from a 250gr .338wm. TKO of 34.9 vs 32.6 for the 338wm..

..t

Most likely different calculators. I use This One for my research. I bet there are several others out there that lead to slightly different results. It shows the Hornady factory 250 as 2678 ft/lbs and a TKO factor of 431 as a comparison. What is the velocity that .338 WM result is based upon?

EDIT: I use the term TKO synonymously with Efficacy as defined as:

"Efficacy is a measure proposed by L. Neil Smith. It is defined as energy in foot pounds multiplied by projectile cross-sectional area in square inches. Neil says that this is a pretty good indicator of the relative efficacy against live targets of different projectiles and loads. In an email about this page, Neil wrote, "I'm not absolutely certain of its applicability to rifles (although it looks pretty good and is fine for slugs and rifles like .45/70). There are other factors at work above 2000-2500 feet per second. But every year that passes convinces me more that this is the perfect program for predicting handgun performance."

Hoot

[Hoot]

...snip...

I use the term TKO synonymously with Efficacy as defined as:

"Efficacy is a measure proposed by L. Neil Smith. It is defined as energy in foot pounds multiplied by projectile cross-sectional area in square inches. Neil says that this is a pretty good indicator of the relative efficacy against live targets of different projectiles and loads. In an email about this page, Neil wrote, "I'm not absolutely certain of its applicability to rifles (although it looks pretty good and is fine for slugs and rifles like .45/70). There are other factors at work above 2000-2500 feet per second. But every year that passes convinces me more that this is the perfect program for predicting handgun performance."

Hoot

Interchanging the values with the names no doubt can produce confusion because the results, though related, are different. Taylor's value is derived from bullet diameter and Smith's value is derived from bullet cross sectional area.

Now with that being the only difference, why Taylor's equation gives an edge to the 250gr at 2200 fps and Smith's equation gives an edge to the 200@2700 is beyond me. Diameter is a component of cross sectional area, so you'd think that they would track linearly. Beats me...


Hoot

[Jim in Houston]

Diameter is a component of cross sectional area, so you'd think that they would track linearly.

The relationship is not linear. Cross sectional area is a function of the square of 1/2 of the diameter, so if the diameter is doubled, the cross sectional area goes up by a factor of 4. TKO's computed on the basis of cross sectional area will increase much faster than those computed on the basis of diameter.

If I remember my geometry correctly, that is.

However, this means that one of the calculation methods will give incorrect results. Since we are not talking about doubling the diameter (or anything near it), the incremental variations may be small, and if you stick to one method, you could reasonably compare results for one cartridge vs another.

[wildcatter]

Yup, What the Hoot and Jim said..

..t

[rohk]

ok, puttin the 160's on hold till i get a faster powder, got a best group of 1.232" at 51 grains lilgun top speed 2690 fps. I think they can go faster.

I got some horanday .451 200 gr HP XTP gonna see how they hold up.

[Hoot]

ok, puttin the 160's on hold till i get a faster powder, got a best group of 1.232" at 51 grains lilgun top speed 2690 fps. I think they can go faster.

I got some Hornady .451 200 gr HP XTP gonna see how they hold up.

Don't shoot them over a chrony! At least until you see how crazy they fly. I still have a piece of a 230gr XTP HP jacket stuck in the front of mine.

If you simply can't resist, load those 200s over 36gr Lil Gun and a hot primer like WSR or 7 1/2. Seat to just bury the front cannelure and taper crimp to .476 measured as close to the edge of the mouth as possible. Catching a cannelure with the taper crimp increases neck tension witch is mother's milk for this caliber. That'll put you around 2200 fps to start. Use a large backboard so you can see where they pattern.

For those 160's pick up a bottle of 2400. It is spherical, so use a hot primer mentioned above. If you want to go safe, start with 34gr. That'll leave a lot of space in the case. If it were me, I'd fill the space up to the base depth of a seated bullet with grits, separating the powder from the grits with one ply disks of toilet paper cut using a case with a sharpened mouth as a punch. Drop the powder, insert the disk, lightly tamp it down flat using the butt end of a 7/16 drill bit. Add a measured amount of grits to each load, the weight of which is determined by experimentation. Don't just go by sight. If you want a fuller case of just powder, then use Lil Gun. Maximum usable non-compressed case capacity with the bullet seated to bury the cannelure will be around 44gr of Lil Gun. That's too much, so don't even think about starting anywhere near there. I want you to be able to type your results.

Hoot

[rohk]

Shot the 200 Grain test loads Sunday, pushed them pretty hard. No signs of them disintegrating. Best load 47.6 Grains Lil'gun.


Yes i shanked one.