Range Report .270 Win Bullets?

[SN13]

I searched this section of the forum for anything regarding .270 or 270 or .270 win, etc.

Nothing.

I understand that the .270 is not the most popular caliber on this board. Maybe that's an understatement.

Anyway, I've looked at Berger VLD, Sierra MK, Nosler AB, and the best BC in a 140gr bullet is Nosler AB w/ .496

BVLD 140gr: .487
SMK 135gr: .488
NAB 140gr: .496

I'm new at this, but understand that BC is very important in maintaining Velocity for shooting further.

Are there any other makes/brands out there which can top these bullets in BC? Also, I noticed that SMK has multiple listings of BC based upon the velocity. Why does the BC decrease as velocity decreases?

Berger Recommends a 1:10 twist for 150gr. 1:11 Twist for 140/130gr. If I have a 1:10, will I be ok shooting the 130/140? Or will the twist rate be too high? Thanks!

 

[Scimitar]

Re: .270 Win Bullets?

1/10 twist will be fine. Sierra shows a different BC because it does change as your bullet loses velocity. Most companies just give you the high G1 BC number. The BC just drops a certain amount as speed decreases. I can't give you the scientific explanation, it just does. A more accurate BC is to use the G7 model which pretty much stays the same throughout normal speeds.
Hard to find actual G7 data foe all bullets. Brian that works for Berger has most of them. Hope this helps.

 

[SN13]

Re: .270 Win Bullets?

Any information Helps. I don't know what G1 and G7 actually mean though. Besides G1 must be the BC that starts high and decreases? G7 is the what? Average BC from 3000-2000FPS? I'll give it a search on Google to try and figure it out.

Edit:

So I googled it and found that G7 is the BC for more Aerodynamic bullets? But then I see that Bryan at Berger lists out some G1 and G7 BCs for some .30cal projectiles and the G7 BCs are like .243 vs .505 G1 numbers.

I'm still confused but now I have more information on the subject.

 

[BryanLitz]

Re: .270 Win Bullets?

The numeric value of a BC referenced to the G7 standard is lower because the G7 standard is lower drag than the G1 standard.

In other words, if you compare the 1/4 mile track time for your '98 Mustang Cobra against an '85 VW bug, you will have about 200% better performance. If you compare your time against a '95 Camaro SS, you may find your time is only 5% better or worse.

Referencing the BC of a low drag bullet to the G1 standard is like comparing your race car to a VW Bug so that's why the G1 BC is higher.

In reality, the G1 and G7 'standards' represent projectile shapes. The G1 standard projectile is flat based with a short blunt nose and has much more drag than a typical modern long range bullet. The G7 standard has a proper boat-tail, and a moderate length secant ogive so it's drag compares quite closely to that of a typical long range bullet. Not only is the magnitude of the drag similar, but the drag changes the same with velocity so the G7 BC is constant.

It probably feels like you jumped into the deep end of the pool. Here are some simple instructions for using the G7 BC's:
Go to:
http://www.eskimo.com/~jbm/calculations/traj/traj.html
and enter the G7 BC in the field for ballistic coefficient. BE SURE TO SELECT G7 ON THE DROP DOWN MENU. If you don't tell the program you're giving it a G7 BC, it will interpret the input as a G1 BC by default and the results will be useless. Fill in the rest of the fields as you would normally and click calculate. The resulting trajectory will be as accurate as the rest of your inputs.

Good luck,
-Bryan

 

[Scimitar]

Re: .270 Win Bullets?

Thanks for the assist Bryan

 

[SN13]

Re: .270 Win Bullets?

Yes,

Bryan also emailed me the G1 & G7 BCs for Berger's .270 Hunting Match VLD rounds.

130VLD: 0.452/0.231
140VLD: 0.487/0.249
150VLD: 0.514/0.263

Using http://www.eskimo.com/~jbm/calculations/traj/traj.html, I cannot get the G7 BCs to work. Keeps telling me "Syntax error"

EDIT:

Bryan Also informed me that the 135gr SMKs are:

0.496/0.253

 

[BryanLitz]

Re: .270 Win Bullets?

J,
It's working fine for me. Remember you can't enter anything but numbers in the BC field. Try re-opening the page and go straight to calculate with all the default inputs.
If that works, then go back up and put in the BC (the decimal and digits only), select G7 from the drop down menu, then click calculate again.
Keep changing one thing at a time and clicking calculate until you find the input that it doesn't like.
-Bryan

 

[SN13]

Re: .270 Win Bullets?

Hrm.

Using exactly the same 200yrd Zero, 140gr .277 projectile @ 3000fps:

G1 - .487
500V - 2092.9 FPS - (-7.3 MoA)
1000V - 1381.8 FPS - (-27.3 MoA)

G7 - .249
500V - 2109.1 FPS - (-7.2 MoA)
1000V - 1375.4 FPS - (-26.9 MoA)


Very interesting. The G7 has more velocity at 500 but less at 1000 but the G1 has a bit more MoA drop in both places.

 

[BryanLitz]

Re: .270 Win Bullets?

It is interesting.
For standard long range bullets with boat-tails and 'non-blunt' noses, you can consider the G7 calculations to be "truth data" (assuming all other inputs are accurate).

Any difference between that and the trajectory predicted by the G1 BC is error incurred by the non-representative G1 standard.

It's encouraging to see the growing interest in the G7 BC's. It truly is a better way.

-Bryan

 

[SN13]

Re: .270 Win Bullets?

Bryan,

I think I'll give a box of Berger VLD's a try and compare them to Nosler AccuBonds using the same Load, Same O-Give distance, same brass, etc.

I'd like to see if the reported .496 BC is really that High or if the .487/.249 BC that berger has for their 140gr. is equivalent.

Come to think of it, I don't know if .496 v. .487 will be visually different at 500 yards.

EDIT:

Running the Calcs on both show a 0.2" difference in drop at 500 w/ 100yrd Zero.

At 1000yrds it opens up to 3.6" difference. So while I may not notice a difference @ 500, @ 1000, if it really is better, there would be a difference.

 

[BryanLitz]

Re: .270 Win Bullets?

I'll go out on a limb...

According to my tests;
In 30 cal, the 165 and 180 grain Ballistic Tips have essentially the same BC's as the 165 and 180 grain Accubonds.
In .270 cal, I've only tested the ballistic tips, but I suspect they're the same BC as the Accubonds based on the .30 caliber results.
Having said all that, I will predict the BC of the .270 140 grain Accubond to be very close to .444/.227 (G1/G7), which is what I measured for the 140 Ballistic tips in that caliber.
These measurements were done on the same day that I tested the Berger .270 cal VLD's for BC, so they're a fair comparison.

I'll be curious to know how your tests turn out.

-Bryan

 

[SN13]

Re: .270 Win Bullets?

According to Nosler, their 30cal Ballistic Tips and Accubonds are exactly the same BCs.

When looking at the .270's though, the BT 140 shows .456 BC/.261 SD/1.296 OAL. The AB 140 shows .496 BC/.261 SD/1.310 OAL.

I don't know if an increase in OAL of .014 can increase BC by .040 so maybe this is a typo on their behalf.

You tell me, you're the master Ballistician.

~SN

 

[BryanLitz]

Re: .270 Win Bullets?

In the case of the .30's, the Accubonds are longer but it's because of a longer bearing surface. Since theirs more copper in them, they have to be longer to achieve the same weight (copper is less dense than lead).
A slightly longer bearing surface will not affect BC by a measurable amount.
IF the 270 cal 140 accubonds have the same ogive and heel as the 140 ballistic tips, they will have the same BC. I can't say for sure since I don't have any samples of the 140 accubonds. I suspect they are the same, and the BC I measured for the ballistic tips (.444/.227 G1/G7) will apply to the accubonds.

You'll have to shoot them and let us know for sure.

-Bryan

-Bryan

 

[Nocalphoenix]

Re: .270 Win Bullets?

Bryan,
Any chance of getting the G1 and G7 values attached to the website? I know its sexier and more of a market comparison to use the G1 but it seems the G7 would be a more appropriate way of labeling most of the Berger lineup.

As a side note anyone know the G7 value of the 115Dtac? G1 is .585...

 

[flyboy]

Re: .270 Win Bullets?

Just get the 150gr VLD's and call it good. They shoot lights out in my 270 and are now the only thing traviling down the tube weather I'm hunting paper or meat.

 

[Cmonroe]

Re: .270 Win Bullets?

Don't overlook the little 135 smk, that has always given me great results with the 270

 

[ChadTRG42]

Re: .270 Win Bullets?

I have shot a lot of long range with my 270 Win, and I would look at the 135 SMK or the Berger 130 grain. If you are shooting a factory 270, I think you will run into accuracy issues beyond 800 yards. After 800 yards, mine would not shoot well. From 800 and in, it would do great. So, you will not be able to get the benefit of the heavier and higher BC bullets for the longer ranges. This is why I would look at the lighter bullets, and take advantage of the flatter trajectory from 800 and in.

 

[SN13]

Re: .270 Win Bullets?

Chad, I think i'm going to run some factory loads to see what my gun likes (130, 140, 150). If it likes the 130/140 I'll be getting the 135 SMK and the 140 Bergers and working loads for each. I may just end up with the 135 SMK.

What kind of Velocities will I see as my max with the 130/135gr bullets? 3000? 3200?

I've seen some reload data online but I'll start at -10% and work my way up, as these seem like nearing warm loads.

How's Alliant Reloader 22? Some of the best loads i've seen online for 130/135gr have been with AR22.

Thanks!

 

[ChadTRG42]

Re: .270 Win Bullets?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SN13</div><div class="ubbcode-body">I think i'm going to run some factory loads to see what my gun likes (130, 140, 150). </div></div>
If you reload, then this won't matter. You develop the load to shoot well in your gun. So, the factory ammo won't tell you anything, really. Unless you plan on shooting the factory ammo only, which it sounds like you will be reloading.
I run IMR4350 with the 135 SMK at 2995 fps avg. I could push it faster, but it shot very well at this velocity. I think my charge was 54.6 or 55.6 grains (I remember it was .6 something) of IMR4350 with a Fed 210 and seated long.
R22 would be a good choice. You will get more velocity with the heavier bullets with it.

 

[SN13]

Re: .270 Win Bullets?

Alliant R22
CCI 250 Primers

Now, what brass should i use?

 

[ChadTRG42]

Re: .270 Win Bullets?

Whatever brand you can get enough of the same head stamp to load up as many rounds as you need. Any Rem, Win, Nosler, Frontier (Hornady) brass will work. Federal (FC) is ok, but will need more trimming since it's softer. Honestly, I bought a ton of once fired for my 270 at a local shooting range really cheap, and use them. Sort them out and throw away any damaged or cases you don't want to use. A few loads I use Rem brass, the others I use Win or Frontier. Just once you start with that brass, stay with it. Otherwise the different neck thicknesses and case capacity can change up your load.

 

[SN13]

Re: .270 Win Bullets?

So I loaded my first batch for my ladder test.

3.43 OAL

Charges varied from 55.0gr to 60.5gr along that 17 batch.

My reloader manual has RL22 at a max of 60gr. But the standard OAL for the .270 is 3.34" But I loaded mine to just touching the lands so I'm 1/10th of an inch long. And it still fits in the mag!

Gonna run a ladder test at 200 to see if i can find the "sweet spot" and also to test for pressure signs.

I started much lower than I probably needed to because I'm using CCI250 Magnum primers and don't want to start off at 58gr which is too close to max for my liking using the Magnums.

IIRC, my loads go:

1 - 55.0
2 - 55.5
3 - 56.0
4 - 56.5
5 - 57.0
6 - 57.5
7 - 58.0
8 - 58.3
9 - 58.5
10 - 58.8
11 - 59.0
12 - 59.3
13 - 59.5
14 - 59.8
15 - 60.0
16 - 60.3
17 - 60.5


I was thinking about loading 2 more (for a total of 3) for the 58.0, 58.5, 59.0, 59.5, and 60.0.

Should i do this or just wait until my next outing to worry about groups? Or should I have 2 of each between 58 & 60 to have a verification Chrono reading & hit on target??

AND should i start my loads at the center of a ladder flat spot? Say if my loads chrono:
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Would I want to start at about 58.5 and work from there? Or what? How accurate is the ladder (Audette) method???

Thanks guys!

 

[kyreloader]

Re: .270 Win Bullets?

Just shoot the ladder and find out where you group together. Then shoot groups at the areas where the shots group together. You will find the powder charge that way, then play with OAL to find the optimal load for your gun.

 

[SN13]

Re: .270 Win Bullets?

Thanks KY-Jelly-Personal-Lubricant-Reloader.

OK, in all seriousness, Thanks Kentucky-Reloader. I'll shoot my ladder test @ 200yards on Sunday and then work from there. I'm loaded to just barely off the lands but I'm using an OAL seater and need to get an o-give seater.

 

[SN13]

Re: .270 Win Bullets?

So I shot the ladder test this weekend.

I had no pressure signs at 60.3gr of powder. At 60.5 i noticed a small shiny spot on the rim of the cartridge. Is that where I'd see the extractor mark or would it be on the base of the cartridge where the headstamp is?

I had no sticky bolt or unusual recoil.

@ 200 yards the shots climbed the page of the target until the final 6; 59.3, 59.5, 59.8, 60.0, 60.3, 60.5 all ended up in a cluster at the top that measured 1.85".

My highest velocity was 3131fps in that group and the lowest was 3054fps (Might be a bit off, recalling from memory and my notes are at hoome.) I think I'm going to test some loads at 59.8 and also make up single loads of 60.6, 60.7, 60.8, 60.9, 61.0 to test out my max load area.

I will post a picture of my Ladder test later but something strange happened. The first shot missed the target Low, the second and third shot printed almost the same height, about 12" low and an inch apart, the 4th & 5th grouped 1/2" apart horizontally about 6" low, same with the 6th & 7th but 3" low, 8th & 9th 1/2" apart and inch low, 10th & 11th 1/2" apart and 3" to the right, then the 12th through 17th all grouped together up top about 2" high and 2" right....

Is it common to see horizontal spread as well as vertical when increasing the powder charge?

 

[kyreloader]

Re: .270 Win Bullets?

Yes, alot of times, my ladder start bottom left and work up to top right. I am sure there is an explanation somewhere on here, but I am not smart enough to know.

I dont think I would bother with any loading over the 60.5g loading. That to me sounds like an extractor swipe and would not go higher than that. I would load up 5 shot groups at 59.5, 59.8 and 60.3 and shoot for groups. I think you will find a true winner and that should be your most accurate powder load.

After the accurate powder load, vary the OAL by 0.005 and shoot some groups to find the most accurate OAL.

 

[SN13]

Re: .270 Win Bullets?

Sounds like a plan KY. ChadTRG42 and I discussed this as well.

I'm going to go for the 59.8 area so will vary the charges around that for groups. 59.5 through 60.3

 

[kyreloader]

Re: .270 Win Bullets?

Keep us updated, this has been fun following along with you.

If you get a chance, post your ladder picture and your upcoming group pictures.

 

[He Shoot Me]

Re: .270 Win Bullets?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kyreloader</div><div class="ubbcode-body">Keep us updated, this has been fun following along with you.

If you get a chance, post your ladder picture and your upcoming group pictures. </div></div>

Yes please do. There are a few of us .270 guys lurking about, this is a very helpful thread.

Thanks,

-Pat

 

[SN13]

Re: .270 Win Bullets?

4/19/09

84* F

13% humidity

30.06 in (falling)

All were loaded to OAL 3.43.

Longest: 3.439
Shortest: 3.427

Here are the Charges & Velocities:

# Chg . Vel DeltaV

01 55.0 2782 -
02 55.5 2814 +32
03 56.0 2902 +88
04 56.5 2903 +01
05 57.0 2886 -17
06 57.5 2952 +66
07 58.0 2992 +40
08 58.3 3008 +16
09 58.5 2994 -14
10 58.8 3005 +11
11 59.0 3046 +41
12 59.3 3054 +08
13 59.5 3084 +30
14 59.8 3097 +13
15 60.0 3087 -10
16 60.3 3102 +15
17 60.5 3131 +29


You can see how the group walked up the page.

First shot missed low. 2nd and 3rd grped together, 3rd and 4th, 5th and 6th etc. etc. until the 12th-17th rounds clustered at the top.

I don't know why rounds with different velocities grouped together. It just happened that way...

here's all 17 rounds.
17
9->16
1->8

You'll notice that there are no noticeable pressure signs. On the 17th round, you can see a shiny spot on the edge of the rim. I believe that's from the extractor closing or extracting and not from pressures. But I'm going to work in the 59.5 area anyway.

 

[itgoesboom]

Re: .270 Win Bullets?

Interesting info.

I picked up a Sendero in .270 Win as well. Right now I am running 130 NBTs over 60gr of H4831SC. I don't have a chrono, so I don't know exactly how fast I am running out of my 26", but the info I have found says it should be around 3,200 fps.

Your data is making me think that I should do some loads with 140gr NBTs or the Bergers.

 

[kyreloader]

Re: .270 Win Bullets?

Your velocity data is interesting also.

If you look at shots 13-16, there is only 18 fps difference between all four shots. That again usually points to this being an accuracy node for you. I still think you will find your load in that range. (My bet is for 59.8g)

Load em up and let us know.

Thanks.

 

[SN13]

Re: .270 Win Bullets?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: friendlyfireisnt</div><div class="ubbcode-body">Interesting info.

I picked up a Sendero in .270 Win as well. Right now I am running 130 NBTs over 60gr of H4831SC. I don't have a chrono, so I don't know exactly how fast I am running out of my 26", but the info I have found says it should be around 3,200 fps.

Your data is making me think that I should do some loads with 140gr NBTs or the Bergers. </div></div>

Yah, my numbers are out of a 22" barrel.

Once I get a really good load worked up, i'm going to grab some 150 Bergers and see how they function. It's possible that I could push the 135s a bit faster if I were using RE19 instead of RE22. W/60.5 I'm not at max pressure but I'm at 99% load capacity.

 

[itgoesboom]

Re: .270 Win Bullets?

Anyone happen to know the G7 BC of the 130gr NBTs?

 

[SN13]

Re: .270 Win Bullets?

If their .435 G1 is correct, somewhere around .222 G7

 

[kraigWY]

Re: .270 Win Bullets?

Excuse me if I'm butting in into something I dont know any thing about.

BUT:

Are we over complicating things here. Several pages up someone posted a Bal Cal. result using the G1 vs G7 BSs showing that in using the differant BC numbers, there as a .6 inch differance at 1000 yards.

OK Whats the problem? A half inch at 1000 with a 270 win. Now I love the 270, in fact my new FN Model 70 Featherweight in 270 has taking the place as my go to hunting rifle. But a half inch differanc at 1000 yards???

First off I always understood that Bal Cal programs were good for maybe getting you on paper at a giving range, but only as a guide, you really have to shoot it and see what happens.

Even in precission sniping a half inch (.6) at 1000 yards isnt gonna make that much differanc. You are gonna get that (at least) just taking the differance between two rounds out of the same lot of ammo.

Maybe I'm missing something. Like I said this is a subject I don't really know a lot about.

Sorry to butt in. I'm just wondering WHY. What (real or practical) differance does it make wheather you use G1 or G7.

 

[Jerry m]

Re: .270 Win Bullets?

Kraig............this is the internet!

 

[kyreloader]

Re: .270 Win Bullets?

Intellectual curiosity?

 

[He Shoot Me]

Re: .270 Win Bullets?

Kraig........Dude, you are harshing my buzz.

Don't come in here and start making any practical sense, were bored and were trying to build better mouse trap's. Besides my computer is telling me you don't even know how to spell your name right. LOL!

-Pat

 

[BryanLitz]

Re: .270 Win Bullets?

Kraig,
Good question.

<span style="font-style: italic">If the G1 BC is averaged for just the right velocity range</span>, it will return results very similar to a trajectory based on a G7 BC.

However, if the solutions are 'matched' at one range (1000 yards in your example) you will see them diverge at longer range, and will even be different between zero and 1000.

The G7 BC will model a more accurate trajectory over long range because it's less sensitive to velocity. It's possible to get an accurate 'point' solution with the G1 at just one range, but it's validity falls off the farther you get from that 'point solution'.

Furthermore, even if you're matching the drop precisely at some range, often times the G1 predicted velocity will be off. This is important for those who care about striking energy and/or remaining supersonic at range.

The devil's in the details.
Hope this helps,
-Bryan

 

[SN13]

Re: .270 Win Bullets?

Just to clarify. The differences in calculation between the G1 and G7 of the 140gr bullet was .4 MOA @ 1000yrds or about 4". That can make a world of difference.

 

[Jerry m]

Re: .270 Win Bullets?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SN13</div><div class="ubbcode-body">Just to clarify. The differences in calculation between the G1 and G7 of the 140gr bullet was .4 MOA @ 1000yrds or about 4". That can make a world of difference. </div></div>

You can hold inside of 4 inches at 1000 yards with a .270? What and where do you shoot?

Jerry

 

[SN13]

Re: .270 Win Bullets?

Errors have a way of compounding themselves.

If you want to remain in the G1 camp, be my guest. No one is stopping you, but you apparently take offense to those who want to use G7.

 

[Jerry m]

Re: .270 Win Bullets?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SN13</div><div class="ubbcode-body">Errors have a way of compounding themselves.

If you want to remain in the G1 camp, be my guest. No one is stopping you, but you apparently take offense to those who want to use G7. </div></div>

No offense here, just wondering why so much bandwidth over such a small difference. Only real way to know if a particular load is going to shoot in your particular rifle is to shoot it at the distance in which you are interested.

BTW a 130 gr Remington core lock will bracket a 24 inch plate in my .270 Win at 800 yards while the 135 SMK will stay on the plate. No disrespect to Berger bullets, but they were not out when I was experimenting.

Good luck

Jerry

 

[Rookiewiththings]

I'm a 270wincraver myself most my loads (charge) 55.4, 55.8, 56.5, my Tikka T3x Lite seems to like it best in these charging ranges with the 130 grain bullets.

Barnes Ttsx 56.5 powder charge 3.201 COAL
Hornady all copper 55.8 with 3.190 COAL
Nosler E-Tips 55.4 with 3.176 COAL

I don't have a chrono so can't tell how fast each load travels. I don't plan to shoot farther than 21,600".