Ladder test results

[sierracharlie338]

So I did a ladder test today @ 400 Yards. Rifle is a stock 700 VSS in 220 Swift shooting 50g VMax. These were my charge weights for the second round of ladder tests for this rifle.

1-36.1
2-36.4
3-36.7
4-37
5-37.3
6-37.6
7-37.9
8-38.2
9-38.5
10-38.8
11-39.1



I see2,3,4 and 5,6,7 but this rifle seems to like the rounds hot such as #9 which is over the book max (38.2). Oh the shots with circles are sighters.

I'm trying to get a good pic of what I believe is a extractor mark on the case rim (pressure sign?) but the next three hotter loads don't show same mark. Until I can get that pic up does any experienced loaders have any suggestions to this point?

Thanks

 

[sierracharlie338]

In the color square you can see a line going from left to right. This was located on shot #8 but not on 9,10,or 11.

 

[sierracharlie338]

Help me tom cruise!

 

[dauntedfuture]

How far away is this target? What kind of bullets are you shooting? What kind of realistic expectations of accuracy do you have for this rifle?

For testing any rifle, further to the is generally better as it will spread the groups out a little bit. I find that 200yds is a good compromise. Also consider that in a .220 the wind will move those light fast bullets at 100 and 200 yds. What is the velocity for each round fired? I normally see "nodes in velocity" that correspond to the nodes in the target. .3g is also a pretty small increment for a .220 but it will work. I use .3 in .223 and .5g in .308.

With all that said, shots 2-9 are all kind of close, I cant tell from the target but I figure 1.5" or so. I think this could be a 100 yd target, so that's a 7 shot 1.5 MOA group and that's a good representation of what factory rifles will realistically do. The majority of factory rifles are good for 1-1.5 MOA or so. There is a reason why a custom barrel costs what it does. Yes, I have some that shoot better then that from the factory and many of us do but ill submit that for everyone that claims "their rifle will shoot .25 MOA all day long" only 1 in 5 can produce a real .25 MOA 5 shot, let alone 10 shot group.

With so little information to go on regarding velocity and bullets, I suggest that you might try another bullet. 52g Flat base bullets will shoot well but will just punch holes in a gopher 1/2 of the time. A 40-50Bt bullet should work well. For deer a bonded 55 should work well but will not shoot as well as the varmint or match bullets.

Take a look at sierras accuracy load and try it, those loads work well in a variety of rifles. Google "skim bedding" most of these factory varmint guns are a little sloppy in the bedding department and 12.00 of bedding material will tighten things up a little.

Are you getting the velocity you want with your given bullet? If you are not then try another powder.

Hope this helps.

 

[sierracharlie338]

As stated in the initial post the test was done at 400 yards. The yards was not behind the 400 initially but that has been fixed.

Shooting 50g Vmax (also added to first post)

This is a very good shooting gun for a factory gun. Sub MOA at 100

I will give you the lack of info on velocity as I do not own a chronograph. I may have access to one shortly but not currently.

 

[mdmp5]

View attachment 49627


In the color square you can see a line going from left to right. This was located on shot #8 but not on 9,10,or 11.

Pressure is typically indicated by an ejector mark, not an extractor mark. Look at the bottom of the head for a circle

 

[dauntedfuture]

I must have missed the range. If those 7 shots are at 400 yds and are under 4" then that's a solid shooting rifle. I would just load at the 6 powder charge, go shoot to verify with a 5 or ten round group and call my load development a day if it works. Barrel life is short with that.220 hot rod.

 

[Deadshot2]

If this were one of my ladder tests I'd be looking for my best accuracy load around #3, #4.

Next "node" would most likely be around #8.

That's just my view.

 

[sierracharlie338]

No prob daunte. Thanks for the input

 

[sierracharlie338]

Pressure is typically indicated by an ejector mark, not an extractor mark. Look at the bottom of the head for a circle

If that's the case there is definitely not any pressure signs as I checked thoroughly for those type of signs.

 

[mdmp5]

From what I can gather from your original post, you are concerned that your hottest loads are working the best for you, although I cannot make a clear call if that is the case based on your test target. I would see if you could repeat the test to shoot a bit tighter; you may have pulled some shots.

In any case, if your best results are coming from loads over book max, do not fret. As long as you have no clear tangible evidence that you are approaching high pressures, then you are good. A good lead sign of pressure is your velocity. Do you have a chronograph of any sort? I do not know 220 swift velocities off the top of my head, but for example, if your load is approaching say 3800, you know that you might be somewhat close to high pressure.

 

[sierracharlie338]

I don't have a chronograph at the moment but working on that. Guess that will tell me a little more to this equation.

 

[tylerw02]

When I do a ladder teat I always try to from low to high and have enough range in my loads to find my upper limit---I want to hit ejector marks so I know where're pressure is as where I can go no hotter.


I always try to do two tests. One starting at the bottom, go up to pressure. Then start again a few minutes later, separate sheet, and work down from the round below where the pressure started.

I take the leftover rounds now deemed too hot and pull the bullets, and reload them at the charge wright that appears to be within the node. I'll take that charge weight and take ten it twenty rounds and shoot them at the range I'm shooting and shoot them into a target to verify accuracy. Then I'm done.


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[sierracharlie338]

I might try loading up some more and go from high to low. Thanks for the input.

 

[steve123]

Of this test #6.

 

[sierracharlie338]

Of this test #6.

Why not 9? Just curious.

 

[tylerw02]

Because 10 is extreme.


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[steve123]

Why not 9? Just curious.

Because 9,10 and 11 are square out of the node and probably up there in pressure.

Look at the small vertical of 5,6 and 7.

 

[tylerw02]

6 because 5 and 7 are acceptable. Do it again and confirm.


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[sierracharlie338]

Ok so I think I see it. I measured the group and from hole 8 to 6 is roughly 3 3/4 inches. I also measured the spread height of 5-6 and that is only slightly over an inch.