Range Report 338 shooters.... I need some ballistic calcs

[garandman]

Trying to figger out if a 70MOA Leupold Mark 4 will reach out a mile

Data:

300 gr .338 SMK's
2600-2650fps (I guess, the rifle is being built)
Not sure of ballistic coefficient
29" bbl

What else ya need to run calcs for me?

Very appreciative.

 

[psinclair]

JBM - Calculations

Give this a whirl.....

 

[SnkBit]

It takes me 16.9 mil shooting the 300smk at 2810fps. That's about 58 MOA. If you have a 40MOA base you should be good. I don't think you'd make it with a 20MOA base at your velocity.

 

[Lowlight]

With a 29" barrel you better push those 300gr pills faster than 2650fps,

If I remember right, a 20" AX will push a 285gr at 2650fps... at 29" you should be well over 2800fps otherwise what is the point. The 300gr bullet is not the end all people claim when it goes too slow. The 285 is a better all around bullet, we proved that at Gunsite with our bullet test / ELR Shoot out.

 

[garandman]

Great info, please keep it coming....

 

[jfields]

You should be able to send a 300 SMK @ 2850 out of a 29" tube. It takes 63.7 MOA at seal level to get to a mile with a 100 yd. zero with that bullet at that velocity.

-J

 

[garandman]

You should be able to send a 300 SMK @ 2850 out of a 29" tube. It takes 63.7 MOA at seal level to get to a mile with a 100 yd. zero with that bullet at that velocity.

-J

Is it true as elevation increases, air density decreases, which means resistance to bullet flight decreases, and bullets drop slower?

The scope in question has 70MOA adjustment. I'm getting a 20 MOA base. That gives me 90 MOA to play with (methinks... ? ) and I should be good. I think...

 

[SVG308]

Is it true as elevation increases, air density decreases, which means resistance to bullet flight decreases, and bullets drop slower?

The scope in question has 70MOA adjustment. I'm getting a 20 MOA base. That gives me 90 MOA to play with (methinks... ? ) and I should be good. I think...

Wrong - the 70MOA is total travel. You will have in the neighborhoood of 55MOA w/ a 20MOA base.

 

[E. Bryant]

The scope in question has 70MOA adjustment. I'm getting a 20 MOA base. That gives me 90 MOA to play with (methinks... ? ) and I should be good. I think...

The 70 MOA is the total adjustment in the scope, top-to-bottom. Assuming that a lot of other things being perfect (and they rarely are), you'll only be able to use half of that - 35 MOA total, minus whatever you consume to get the rifle zero'd at a particular range (usually a few MOA at 100 yards/meters, depending upon scope/bore offset).

The 20 MOA base is added to that 30-35ish MOA of scope travel, which gets you somewhere in the 50-55 MOA range of total adjustment. But if you needed to put on some windage to get the rifle zero'd, and/or need to adjust windage to account for wind and other variables at maximum range, then you may not be able to use the full elevation adjustment.

It would appear that you will need a scope base with additional slope (which might get to the point where getting a zero at 100 yards is difficult), or a scope with additional elevation range, or you will need to top-out the scope and use holdovers to get to the desired range.

 

[garandman]

The 8.5 - 25x Mark 4 has 85MOA adjustment. With a 30 MoA base, that'll give me 70+/- MOA adjustment.

The JBM calculator give s me:

300gr .338 SMK
Ballistic Coeff: 0.768 at muzzle
300 yard zero
70 degr F
1500ft above sea level (typical for where I'll be shooting)
2825 muzzle velocity


56.3 MOA drop at 1700 yards.

This look right?

 

[bodywerks]

With a 29" barrel you better push those 300gr pills faster than 2650fps,

If I remember right, a 20" AX will push a 285gr at 2650fps... at 29" you should be well over 2800fps otherwise what is the point. The 300gr bullet is not the end all people claim when it goes too slow. The 285 is a better all around bullet, we proved that at Gunsite with our bullet test / ELR Shoot out.

If you're talking about the Hornady bullet, i can't help but be completely turned off by the shockingly low BC. I would love to see an amax version in the high .7s though.
FWIW, garandman, my mag length (3.750) 300otm's are flying at 2700 out of my 29" barrel under 90gr retumbo.
Interestingly, i loaded some 91gr loads and ran them to 3.850. It got me to 2800, just that one extra grain, but bolt lift was shockingly heavy, almost like my savage was. I guess the loss of a hundred thousandths jump caused too much of a pressure spike. I only sent two of those rounds down range and stopped. I'm going to seat the other 8 back down to mag length and try them again, because I'm sure i should be able to run at least 92-93gr without pressure and get at least 2800+...

PCR/XLR/TAC338 http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111453_255_zps1b498f0d.jpg http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111325_951_zps290ebdd0.jpg

 

[Lowlight]

If you're talking about the Hornady bullet, i can't help but be completely turned off by the shockingly low BC. I would love to see an amax version in the high .7s though.
FWIW, garandman, my mag length (3.750) 300otm's are flying at 2700 out of my 29" barrel under 90gr retumbo.
Interestingly, i loaded some 91gr loads and ran them to 3.850. It got me to 2800, just that one extra grain, but bolt lift was shockingly heavy, almost like my savage was. I guess the loss of a hundred thousandths jump caused too much of a pressure spike. I only sent two of those rounds down range and stopped. I'm going to seat the other 8 back down to mag length and try them again, because I'm sure i should be able to run at least 92-93gr without pressure and get at least 2800+...

PCR/XLR/TAC338 http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111453_255_zps1b498f0d.jpg http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111325_951_zps290ebdd0.jpg

Ignorance is bliss...

If you think Hornady will shocking underperform you are not paying attention.

And if you can't push the 300s fast enough, you are not taking advantage of the advertised BC to begin with, and you're results will vary far greater because we found the 285gr to work across the board in more rifles, that includes, we shot off these bullets on paper at 1500m then on steel beyond 2000m.

The 300s were not what they should be in a 338LM because they are not going fast enough. They varied downrange to a higher degree and were not nearly as consistent as the Hornady ammo. Factory and Handloads... In fact after the ELR test, you saw most guys coming to the next XLR Class at Gunsite using 285s and nobody was disappointed.

You can run all the numbers you want, reality is a different animal.

 

[bodywerks]

I agree, its just a low BC for such a heavy bullet. I might give then a try after i use up the 700 Bergers i got here

PCR/XLR/TAC338 http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111453_255_zps1b498f0d.jpg http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111325_951_zps290ebdd0.jpg

 

[SnkBit]

Lowlight,

At what velocity does the 300SMK's BC become advantageous? I'm only running 2810fps and it seems to be working quite well. I'm shooting an Edge so higher velocities are possible if necessary but I don't see the need in tearing up brass at this point.

 

[garandman]

For the record....

The build is a 338 Norma Magnum

 

[maccrazy2]

I am shooting a savage 338 lapua and am throwing in the towel on the 300smk's I cant get the speed up where I need it and still be able to get the brass out of the chamber. I just chroned yesterday a whole range of charges.
lapua brass.
fgmm mag primers
h1000 powder
powder measured on a chargemaster and double checked before charging the case because if odd velocity fluctuations previous session
shot in 87deg
86 gr cold bore 2707fps easy to extract
86.5 2696 easy
87 2697 slightly harder to open bolt
87.5 2688 stiff bolt
88 2710 stiff
88.5 2600 little stiff
89 2763 trouble extracting
gun sat for a bit then fired
89.5 2763 easy to extract
90-91 all stiff

my original load workup was 92gr h1000 and if the gun was kept cool it worked fine. it ran 2800 range. when I shot the magnum match in Raton I started sticking cases as the barrel warmed up. At my home range and under slow fire it shoots that load fine? Now I am way over book max but the book was way to slow for my taste. I know a few guys running the 300smk faster than me with less powder but they are in other guns with better barrels so it is what it is.
I am going to order some 250smk and some of the 285s and see what happens.

 

[bodywerks]

H1000 is not a speed powder and the savages are notorious for sticky bolts. Try retumbo, but getting 2800 out of a 26 inch barrel is asking a bit, especially out of the savage, with its rough, tight chamber.
Also, try your 86gr load again after about 10 fouler shots. I bet its less than 2700 after that.
And other MAJOR factors that result in inconsistent velocities is bullet runout, inconsistent neck tension, dirty case mouths, and inconsistent ogive seating depth.
Of course, in a non match grade non precision chambered barrel all bets are off as well. All efforts to load perfect ammo that gets put in a crooked chamber are wasted efforts.
Check the runout of your fired cases. If anything more than .0005-.0008(yes, ten thousandths) and you'll just have to accept inconsistency. Non concentric fired cases mean a non concentric chambered barrel, which is possible in a factory savage.
PCR/XLR/TAC338 http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111453_255_zps1b498f0d.jpg http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111325_951_zps290ebdd0.jpg

 

[maccrazy2]

H1000 is not a speed powder and the savages are notorious for sticky bolts. Try retumbo, but getting 2800 out of a 26 inch barrel is asking a bit, especially out of the savage, with its rough, tight chamber.
Also, try your 86gr load again after about 10 fouler shots. I bet its less than 2700 after that.
And other MAJOR factors that result in inconsistent velocities is bullet runout, inconsistent neck tension, dirty case mouths, and inconsistent ogive seating depth.
Of course, in a non match grade non precision chambered barrel all bets are off as well. All efforts to load perfect ammo that gets put in a crooked chamber are wasted efforts.
Check the runout of your fired cases. If anything more than .0005-.0008(yes, ten thousandths) and you'll just have to accept inconsistency. Non concentric fired cases mean a non concentric chambered barrel, which is possible in a factory savage.
PCR/XLR/TAC338 http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111453_255_zps1b498f0d.jpg http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111325_951_zps290ebdd0.jpg

Nice rifle. I went the savage route because this match is only held 3 times a year and is just for fun. Couldent justify the cost of a full custom build for that. The irony is that the attendance dropped and now they are allowing other calibers to compete so now have the option to use other rifles I already owned. Oh well it never hurts to have one more.
At this point I just want to work up a decient load that I wont have issues with when the gun warms up. Also should mention the barrel was fouled on the first shot from the prior weekend testing.
I will say the gun shoots quite well as is. I shot groups with the initial rounds running 2600 and it was quite good for off the shelf. This was before adding the karston cheekrest and really getting it all setup for me. I will measure what it can do shortly when I get my load worked out. On a side note the magneto speed chrono is awsome I have used it the last 2 weeks and love it.

 

[natesguns]

I shoot my 338 to a mile with my mk4 leupold. shooting 300 berger otm's. 2740 MV, 21 mills of elevation. It's maxed at that distance. I've even dialed back a half a mill and held over with my recital. I'm running 20 moa base. I've made good hits at 1800 but like I said its all I've got. 27 inch barrel You should be able to get there I recommend a 30 moa base Wish I'd have gotten one. Good luck.

 

[siglover]

Ignorance is bliss...

If you think Hornady will shocking underperform you are not paying attention.

And if you can't push the 300s fast enough, you are not taking advantage of the advertised BC to begin with, and you're results will vary far greater because we found the 285gr to work across the board in more rifles, that includes, we shot off these bullets on paper at 1500m then on steel beyond 2000m.

The 300s were not what they should be in a 338LM because they are not going fast enough. They varied downrange to a higher degree and were not nearly as consistent as the Hornady ammo. Factory and Handloads... In fact after the ELR test, you saw most guys coming to the next XLR Class at Gunsite using 285s and nobody was disappointed.

You can run all the numbers you want, reality is a different animal.

Very interesting thank you for this information lowlight. I'll be testing the hornady bullets very soon. All the info i was gathering said 300gn was the way to go.

 

[garandman]

I shoot my 338 to a mile with my mk4 leupold. shooting 300 berger otm's. 2740 MV, 21 mills of elevation. It's maxed at that distance. I've even dialed back a half a mill and held over with my recital. I'm running 20 moa base. I've made good hits at 1800 but like I said its all I've got. 27 inch barrel You should be able to get there I recommend a 30 moa base Wish I'd have gotten one. Good luck.

Thank you - right on point. I ordered a 40 MoA base, as I never plan on shooting this gun under 500 (after sight in)