.300 Winchester Magum Bullet Choice - Expanded

[marc357]

Jon,

Thanks for the suggestions, and for taking the time to reply.

I'm with you, I really thought it was some kind of Garbage-in,garbage-out problem, and as you said, normally, one would be happy just to have a functioning, real-world drop chart... but I want to know WHY, dammit.

Yep, this is a perfect example of why there's NO SUBSTITUTE for shooting your Rifle/load/scope combo EVERY HUNDRED YARDS,(or 50 if you can)- and logging the dope in your data book. Change any one of those three elements, and you need to chuck your data book, and start a new one.

I'm using 1:10 twist, pretty standard.

I have checked the scope reticle against a long ruler @ 100yds, measured with a 100-foot tape, not a LRF, although the LRF did agree with the tape. The MOA reticle subtends exactly 1-inch per hundred yards. I also held the rifle steady on a bipod and rear bag, while my son cranked in elevation, 4 clicks at a time, it tracks right with the ruler, all the way to 45 inches/SMOA, which is all the usable adjustment I have past my 100-yd zero. Repeated several times to be sure, going up, coming down, etc. I feel confident about the adjustments.

I am pretty confident about my weather data, I use a Kestrel 4000, which outputs directly to density altitude, if you want it to, saving the computations... I have checked it against 2 other Kestrels, and against the weather station at the school 1/2 mi down the road, via the "Weatherbug" program (pretty handy), and it's good. A thousand-foot change in density altitude only changes the impact about .5 MOA at 1000 yds, not nearly enough of a factor to explain the discrepancy here.

You're right, it almost has to be my chrony data. I have, of course, had wild readings, especially in "weird" light, but usually just 1 shot here and there, so high or low, I knew it was an error, and discounted it. Never got the feeling it was "consistently" reading high (or low)... but what else could it be......?

I think you are correct,that I am dealing with a couple of factors that stack up in the same direction- that the (advertised) BC is a bit optomistic, and my chrony readings are a bit optomistic as well.....

I have been shooting the Bergers, because they shoot so much flatter (25.75 SMOA @ 1000), buck the wind so well (6.0 SMOA @ 1000, with a 10mph full-value wind), and lately, I have been shooting more matches, than I have been hunting. The most fun are the unknown distance matches, no LRF's, no sighters, first shot is for score.... and those slick Bergers are a great mistake eraser, because errors in range estimation, or wind estimation, are lessened. "Shoot right through it", as they say...

But those Ballistic Tips just KILL STUFF DEAD, and I like using them for hunting, but I just haven't had the confidence with them, because I couldn't resolve the dicrepancies we have been discussing.

Thanks again for your time, you're helping me get to the bottom of it, always helps to get a fresh take on it. I'm going to try another chrony side-by side with mine, if I can, and with more than one gun.

Sorry if we've hijacked the thread, the discussion seems somewhat relevant to the bullets that were asked about.

Stay safe, and good shooting!

marc

 

[dogz]

300winnie-for what it is worth the first bullet that I would work with out of that group is by far the 168 TX.

This is one super bullet and I can find no flies on it as far as accuracy goes and the performance on game from yotes to elk has been steelar.

Good luck

Mark D

On a side I would also work up a 168 MK load and do a ton load of work with it. It is a fair bit cheaper to run a boat load of than the TX.

 

[Hired Gun]

When I'm questioning chronograph results I like to line them up end to end rather than side by side. That way they both get a read on the same bullet. That's how I found out my old Chrony was 400 fps slow.

 

[dogz]

Hired we did that last summer with a couple it was quite interesting.

Mark D

 

[Jon A]

One more thought Marc:

Were you shooting these out of the magazine or loading them singly? My 300 will flatten plastic tips in the magazine...not a whole bunch--not anything like a lead tip bullet will flatten--but certainly enough to knock the BC down a notch or two. Enough to turn a .5 bullet into a .4 bullet. Just another possibility.

If not, back to the chrono....

 

[jwp475]

I shoot the 180 TXS out of a 300 wm and have found a bc. of .525 to work for me with my velocity of 3075 fps out to 1000 yards

 

[Jon A]

Well, I'd say there's something going on similar to what is going on with Marc--just in the opposite direction. However you came to that number, the fact is if you had substituted Sciroccos for the TSX's and done exactly the same thing, you would have come up with a .6+ BC. It would really be wonderful if it was that high...but it simply isn't.

 

[ivo]

I like the 180 NAB. They've produced good results on deer, elk and moose. Here's a photo of one recovered from a moose, weight retention was 76% or 137gr. I would rather use 200gr NABs but the 180s shoot better.

 

[Desert Fox]

I had been using 180 grains Barnes TSX since it first came out and the factory published BC of .552 is right on for my rifle. My rifle is the Winchester Model 70 Laredo chambered for 300 Winchester Magnum. My average velocity on this rifle is 3050 fps. I have a drop chart for 5000 ft. elevation and the effective ballistic coefficient for this bullet is .676 on a temperature of 68 degrees. Prior to switching, I was using Hornady 180 grain SPBT at 2975 fps. The Barnes will shoot the same point of impact but 3.5 inches higher than Hornady at 100 yards. The accuracy was about the same so the switch was easy.

 

[300winnie]

ivo,

That is a good looking bullet but I thought the nosler accubond had a boattail design. That bullet looks like a flat base.

 

[300winnie]

Here are some images of the 200 grain Accubond I fired at my cow elk this past fall. The range was somewhere in the neighborhood of 150 yards. The bullet entered slightly right of the tail head with a course to take out the spine. It took out approximately a foot of spine, completely crushing it before it veered of into the muscle (back strap) where I found it after penetrating another 6 or 8 inches. This bullet was also fired from my .300 Winchester Magnum at a muzzle velocity of ~ 3,000 fps. Bullet weight 122 grains, for a retained percentage of 61%

 

[Fotis]

Very nice!!!

 

[jro45]

An accurate bullet that I have found is the Remington 180 gr bullet. I put three in a row at 200 yds. So whats that 5/8" or 3/4". Hoz. With my 300 RUM.

 

[300winnie]

Here is a series of images of a 180 grain Swift Scirocco that I shot a cow elk with three years ago. Again, .300 Winchester Mag with a muzzle velocity of 3,160 fps. We lasered this cow at 608 yards. Bullet broke a rib going in, took out the necessary plumbing, went between two ribs on the offside and lodged under the skin creating a nice bulge.