Huge drop in 100 metres with my 270

17 June 2012, 01:03

I went to the range to shoot some handloads yesterday to confirm what I had found on the last outing when 57 grains of h4831SC behind a 150 grain Hornady Interlock with CCI 200 primers in my 270 gave me the best accuracy at 100 metres.

It is a 1953 Husqvarna, FN action with a 24 inch barrel.

The 100 metre group was about 1 1/2 -inches in size and 2 1/2 inches above the centre of the target.

I'm no sniper and my handloading is done with a little Lee Loader kit with a scale, so 1 1/2 inches is okay with me at 100 metres.

But at 200 metres the group was 5-inches low.

That's a heck of a drop isn't it?

The theory was to try to get a group at 100 metres that would put me bang on at 200.

No, before you ask, I don't have a chronrograph.

17 June 2012, 01:42

chuck375

That doesn't make sense. I shoot 150g Partitions at 3000 fps out of my 270 with 58.5g H4831 SC (a little warm) and sight in 2.5" high at 100 yards. It's dead on again at 250. Here's a link to an online trajectory calculator. It might help. Do you have a scope on it, is it in normal height rings?

http://www.biggameinfo.com/ind...x?page=/balcalc.ascx

17 June 2012, 02:23

BigNate

I think before you look at the gun or bullet you need to check your scale.

17 June 2012, 02:38

p dog shooter

Are you sure it is not you causeing the drop.

I little finch might not show up to much at a 100 would be 2 times the trouble at 200.

Also check the mounts,action screws some thing might be lose.

2.5 at 100 should be dead on past 200.

17 June 2012, 02:47

Alberta Canuck

The first thing I would recommend to you is that you check your scale setting. Make sure the scale is properly levelled, and zeroed each time before you rely on it. Then make sure you have actually set it for 57 grains. That result you are getting sounds to me more like you may actually be getting powder throws of about 47 grains (or less), rather than 57. Velocities might then be slow enough that you'd have a trajectory like a rainbow.

How high up in the case does that charge come? It should be well up into the neck. If it is about at the bottom of the shoulder or any lower, it isn't near 57 grains and could even be 37 grains...which might give a trajectory about like a 30-30, which seems to be what you are getting..

17 June 2012, 03:35

vapodog

At 2.5 high at 100 and 5" low at 200, your velocity is somewhere under 2,000 FPS.....

May I suggest you start all over and check everything.....something is drastically wrong here.

17 June 2012, 05:56

z1r

For a reference point, you may also want to try firing some factory loads to see how they print.

17 June 2012, 06:14

wasbeeman

Proofing against some factory ammo is a good idea.
And, it could be your bench technique. What's your bench set up?

17 June 2012, 06:26

Hublocker

quote:
What's your bench set up?

I go to a public range, rest the foreend on a sandbag, rest the butt on another one and shoulder the rifle, moving it slightly back and forth until the crosshairs are on target.

Got a 1-inch group with my 7x57 shooting like that the same day.

18 June 2012, 02:03

bbell

It may be your shooting style. ie you may have put substantial pressure on the foreend of the rifle when you shot at 100, and not as much pressure when you shot at 200. I have had that happen by leaning into the gun a little harder at 100 than 200. Also what you have the foreend resting on may cause that change . Ie if it is a "hard" material and you put pressure on it the gun will shoot away from the pressure. My explanation isn't very good but I hope you get the idea. consistent hold between 100 and 200 yards

18 June 2012, 02:23

Antelope Sniper

Tell us about the stock and scope.
Any parallax in the scope?
Barrel freefloated?

18 June 2012, 09:55

Hublocker

The stock has been glass bedded.

Scope is an older M8 Leupold 4 power. No parallax.

18 June 2012, 21:35

Bear in Fairbanks

hublocker:
Just for kicks, I ran your info thru my copy of Quickload and it too indicates something isn't right. Firstly, I never depend totally on QL for my load data but use it only as a guide.
I too shoot a .270 Win. with 150 gr. Partitions or NorthForks and with RL-22 and get 2930 fps on my chrono.
QL predicts 2948 fps with your listed load - about where I'd expect if it were my rifle.
For you to be sighted in 2 1/2" high at 100 meters (109 yds.) and to have a drop of 5" at 200 meters (about 220 yds.), your powder charge would have to be 50.6 gr. of H-4831 SC. QL predicts your velocity would be about 2600 fps with that load.
I'm in agreement with the other guys in that something is wrong. 1st thing, IMHO is to check your scale and shooting a box of factory ammo wouldn't hurt either. Try to beg, borrow or steal a chrono too.
Good luck.
Bear in Fairbanks

18 June 2012, 22:29

vapodog

quote:
Try to beg, borrow or steal a chrono

BTW.....I seriously doubt if 2,600 FPS would drop that fast.....my info suggests about 1,900 FPS to drop that fast....

18 June 2012, 22:43

ramrod340

quote:
my info suggests about 1,900 FPS to drop that fast....

I get just a touch over 1900fps for that much drop

18 June 2012, 23:00

wasbeeman

Have someone else shoot the rifle. Someone without any precieved ideas as to what's going on.
You can not only flinch, you can buck a shot. That's where you anticipate the recoil and lean into the rifle.

19 June 2012, 04:35

Fat_Albert

No chronrograph = shooting in the dark.

19 June 2012, 05:09

chuck375

quote:
Originally posted by ramrod340:
quote:
my info suggests about 1,900 FPS to drop that fast....

I get just a touch over 1900fps for that much drop

That's what I got also. There's no way that can be happening with that load of powder. He should be getting close to or over 2900 fps with 57g of 4831

19 June 2012, 19:58

Hublocker

On the same trip to the range I shot my 7x57 using 140 grain bullets in front of 48.5 grains of H4350.

The group printed about three inches high at 100 metres and was still two inches above the bull at 200.

There was no strange drop in the bullet indicating a faulty scale. I'll have to find a way to check my scale anyway and find a chronograph to use.

19 June 2012, 20:06

wasbeeman

... Check your scale.... weigh some bullets.

20 June 2012, 06:05

carpetman1

try shooting it in yards instead of meters. .270 is not a metric cal.

20 June 2012, 19:51

ARWL

Hublocker, I agree. Without a chronograph all of the above replies are potentially helpful good ideas at best.

Some rifles and componenet combinations can be very loose systems that take larger charges to achieve the same as the manuals, or other rifles.

Unfortunately, when relaoding, what we don't measure we don't know.

Yes, firing factory ammo may give you an idea as to a trend (i.e. lower than usual pressure and hence velocity) but that's all.

Try to borrow a chrono, or when you are on the range and see someone with one ask if he will shoot a few shots over the screen with your rifle.

Let him do it; never put holes in another guy's chrono...

21 June 2012, 00:01

Alberta Canuck

What your 7x57 did isn't relevant.

It does not tell you what your scale was truly set at when you loaded the .270 ammo, or the bore diameter you were shooting the load through. (You don't happen to have two rifles just alike, except one is a .270 and the other is a .30-06, do you?)

If you are not willing to set your scale up again, re-set it for 57 grains charge weight, make some more loads which you KNOW have 57 grains of H4831SC in them, and try those, then at least try this...

Remove the bullets from three of your cartridges that were loaded at the same time and with the same load for your errant .270 rifle. Weigh each of the three powder charges from them, and see how much they weigh now.

One thing is for sure, 57 grains of that powder behind a 150 grain Nosler .270 bullet is NOT going to produce only 1,900+ fps muzzle velocity or that trajectory. I don't care how different your rifle's tolerances are from the next one off the assembly line unless yours is a mis-marked .30-06. That just is NOT going to happen with that much 4831 powder and a 150 grain .277" bullet in a .270.

21 June 2012, 07:19

SR4759

quote:
Originally posted by Hublocker:
I went to the range to shoot some handloads yesterday to confirm what I had found on the last outing when 57 grains of h4831SC behind a 150 grain Hornady Interlock with CCI 200 primers in my 270 gave me the best accuracy at 100 metres.

It is a 1953 Husqvarna, FN action with a 24 inch barrel.

The 100 metre group was about 1 1/2 -inches in size and 2 1/2 inches above the centre of the target.

I'm no sniper and my handloading is done with a little Lee Loader kit with a scale, so 1 1/2 inches is okay with me at 100 metres.

But at 200 metres the group was 5-inches low.

That's a heck of a drop isn't it?

The theory was to try to get a group at 100 metres that would put me bang on at 200.

No, before you ask, I don't have a chronrograph.

Before you jump to any rash conclusions reshoot that load and an equivalent velocity load of 4350.

21 June 2012, 08:47

7MMNut

quote:
Originally posted by SR4759:
quote:
Originally posted by Hublocker:
I went to the range to shoot some handloads yesterday to confirm what I had found on the last outing when 57 grains of h4831SC behind a 150 grain Hornady Interlock with CCI 200 primers in my 270 gave me the best accuracy at 100 metres.

It is a 1953 Husqvarna, FN action with a 24 inch barrel.

The 100 metre group was about 1 1/2 -inches in size and 2 1/2 inches above the centre of the target.

I'm no sniper and my handloading is done with a little Lee Loader kit with a scale, so 1 1/2 inches is okay with me at 100 metres.

But at 200 metres the group was 5-inches low.

That's a heck of a drop isn't it?

The theory was to try to get a group at 100 metres that would put me bang on at 200.

No, before you ask, I don't have a chronrograph.

Before you jump to any rash conclusions reshoot that load and an equivalent velocity load of 4350.

Beat me to it, I'd have to agree with this. Not familiar with the 7x57, but if you can use the same primer as the 7x57 loads too that'd be even better.

If you still get this unexplained drop, I think I'd be inclined to take the rifle to a gunsmith and have him check out the bore.

If the drop goes away, you'll know it's either the primer or powder you were using.

21 June 2012, 22:12

Alberta Canuck

Let me ask a some questions, please.

1. Is this load of yours the only ammo you have ever shot through this rifle? If not, what was the other ammo, and how did it do, drop-wise?

2. It appears as if perhaps you bought this rifle as a used one (other than new). If that is correct, have you checked the bore diameter to make sure it really IS a .270? That sounds like an older model rifle to me (1953 did you say?), and it is possible (not likely, but possible) that someone had it re-bored from .270 to .30-06 for some reason or another. If they did, it should have been re-marked, but that doesn't always occur as it should.

3. How about the scope? Was there any possibility some "friend" at the range "tweaked" the adjustment for you during the time you were putting your target up 200 yards? Or, could the scope be an old one worn or damaged internally which has a tendency to move its adjustments due to recoil?

4. Have you used this scope before, on either this rifle or another? Did it come with the rifle? If it did come with the rifle. it is always possible the previous owner used the sale as an opportunity to rid himself/herself of a faulty piece of hunting glass. If you bought the scope used somewhere else, there might be a resason the previous owner wanted to part with it other than what he/she may have told you.

21 June 2012, 22:20

vapodog

Where is Hot Core when you need him?.....

21 June 2012, 22:25

vapodog

If there was an error in setting the scale and instead of setting it at 57 grains.....it was actually set at 47 grains you'd be getting about the 1900 FPS we are seeing in the drop!

21 June 2012, 23:26

Hublocker

quote:
Let me ask a some questions, please.

1. Is this load of yours the only ammo you have ever shot through this rifle? If not, what was the other ammo, and how did it do, drop-wise?

I have shot factory ammo out of it, can't remember if I tried some at 200 though. I think so, and don't recall that kind of drop.

2. It appears as if perhaps you bought this rifle as a used one (other than new). If that is correct, have you checked the bore diameter to make sure it really IS a .270? That sounds like an older model rifle to me (1953 did you say?), and it is possible (not likely, but possible) that someone had it re-bored from .270 to .30-06 for some reason or another. If they did, it should have been re-marked, but that doesn't always occur as it should.

The rifle was given to me some years ago. It is a factory 270, a Husqvarna on an FN action. I have shot a moose and several deer with it using the same load with Nosler bullets.

3. How about the scope? Was there any possibility some "friend" at the range "tweaked" the adjustment for you during the time you were putting your target up 200 yards? Or, could the scope be an old one worn or damaged internally which has a tendency to move its adjustments due to recoil?

It's a 4-power Leupold, had it for 10 years, never dropped it and it has functioned fine.

4. Have you used this scope before, on either this rifle or another? Did it come with the rifle? If it did come with the rifle. it is always possible the previous owner used the sale as an opportunity to rid himself/herself of a faulty piece of hunting glass. If you bought the scope used somewhere else, there might be a resason the previous owner wanted to part with it other than what he/she may have told you.

See above

My country gal's just a moonshiner's daughter, but I love her still.

21 June 2012, 23:27

Hublocker

quote:
Before you jump to any rash conclusions reshoot that load and an equivalent velocity load of 4350.

Good idea

23 June 2012, 10:31

Nakihunter

I totally agree with this post. Many years ago when I started hand loading for centre fire rifles, I used a bench to sight my rifles. I would rest the fore-end on the sand bag and shoot them. Depending on the day I would get erratic groups and stringing. Sometimes I would get a tight group.

Then when shooting off hand I would find that my bullets were hitting the target 2 to 3 inches low! I found this very frustrating. This happened with glass beded rifles as well. I then got an idea and started resting the rifle's magazine area on the sand bag. Bingo - groups became consistant and smaller. No more stringing. No more drops of 2 or 3 inches when shooting off hand of or off my knees.

I am not sure if this is relevant to your problem but I thought I'd share my experience.

Hope you sort this out soon.

quote:
Originally posted by bbell:
It may be your shooting style. ie you may have put substantial pressure on the foreend of the rifle when you shot at 100, and not as much pressure when you shot at 200. I have had that happen by leaning into the gun a little harder at 100 than 200. Also what you have the foreend resting on may cause that change . Ie if it is a "hard" material and you put pressure on it the gun will shoot away from the pressure. My explanation isn't very good but I hope you get the idea. consistent hold between 100 and 200 yards

25 June 2012, 05:06

SR4759

quote:
Then when shooting off hand I would find that my bullets were hitting the target 2 to 3 inches low! I

When you shoot off the bench put your hand under the fore end and grip the rifle. You will feel if you are leaning on the rifle with your face.
Natually when shooting off hand you don't lean 15 lbs of skull on your rifle and support it at the fore end with an extended arm.

30 June 2012, 21:34

Hublocker

yesterday I went to the range at at 100 metres, Winchester factory loads with 150 gr. bullets and my new handloads with 49 grains of H4831SC behind a 150 grain Hornady Interlock printed decent groups at 2 1/2 to 3 inches above point of aim at 100 metres.

At 200 metres the groups were a little bigger but still in the 3 inches above the bull range.

30 June 2012, 21:47

Antelope Sniper

49gr of H4831sc behind a 150gr bullet sounds a little on the cold side.....did you mean 58 gr?

30 June 2012, 23:58

Hublocker

Oops! Yes, it was 59 grains.

01 July 2012, 00:18

505G

So you have solved the problem of the big drop at 200 metres but have you worked out what was causing it ?

01 July 2012, 00:20

SR4759

Any theories about what caused the unexpected difference in drop?

01 July 2012, 01:29

Hublocker

I have no idea.

01 July 2012, 03:48

Blacktailer

You know it is fairly easy to set up a balance beam scale 10gr off. When I load I set my powder charge with the scale and leave the scale right on the shelf in front of me with that charge on it until I decide to weigh another charge.
I have been known to get a number of loads done before I look at the scale carefully and realize that I set it up wrong.

Don't know if this is what happened to you but it seems like one possible explanation. Have you pulled any of the original loads and reweighed them?