215 Berger question

[Hillhunter]

A question for the Ftr gurus, having found a great load @ 1000 yards, is it possible that this will not stabilise @ 300 yards? Or should it be as good, at all distances,

 

[Keith Glasscock]

I don't think it is possible to be good at 1k and "unstable" anywhere along that trajectory.

What are you observing that prompts the question?

 

[Hillhunter]

I was shooting earlier today at 300 with once fired brass which I thought would be better than new brass, I was getting a perfect horizontal but they were at least 5 inches wide over 20 shots, maybe it's my load. I load developed with new brass not once fired, more than likely it's my technique. I don't know,

 

[jsthntn247]

I was shooting earlier today at 300 with once fired brass which I thought would be better than new brass, I was getting a perfect horizontal but they were at least 5 inches wide over 20 shots, maybe it's my load. I load developed with new brass not once fired, more than likely it's my technique. I don't know,

Perfect horizontal or vertical at 300, post wasn't clear.

 

[Hillhunter]

Apologies if it wasn't clear

 

[Trevor60]

If your day was like mine you found a load that had near 0 vertical but had 2.1 inch .67moa horizontal from the seated position on the bench BUT when u went prone your vertical opened up to .68moa and your horizontal went to 1moa. all this at 300 yards

it seems any shoulder pressure (influence) really opened up the groups. I was able to control some of the horizontal only after i started to grip the rifle with moderate pressure. (i am a lefty) the rifle torques away from me.

Tried different recoil pad cants \ I / will limited success it seemed that the cant away \ from my collar bone improved the groups and controlled some of the horizontal.

And just for S's and giggles i had and idea that i needed a larger ignition so i switched the fed 205m to Rem 7 1/2 and to my surprise my best horizontal was with the Remington primers measuring outside to outside gave me 1.1" or 1/3moa but the largest vertical at 1.1moa. (not running a ladder test did affect the vertical)

 

[Hillhunter]

Thanks Trevor 60, I have tried light hold, and I think it likes a firmer hold, you have stated what I suggested, wrong technique, back to practice, but also I think I will try this load again, with maybe. 2 gr up and down with the once fired brass and see what the difference is.

 

[broncman]

I shot one round of 215's today at Oak Ridge and they did very well. Firm hold!

 

[Hillhunter]

Sounds like I need to firm up on my hold , thanks for the replies, I shoot 155's in my 1/12 and it seems to like free recoil , that is what I am used to , now I will try to train the brain to hold on tight

 

[XTR]

I was shooting earlier today at 300 with once fired brass which I thought would be better than new brass, I was getting a perfect horizontal but they were at least 5 inches wide over 20 shots, maybe it's my load. I load developed with new brass not once fired, more than likely it's my technique. I don't know,

This is why I don't shoot the 215s in competition. Your problem is recoil management.

 

[dcali]

I'm curious/concerned about how barrel length impacts the vertical on the 215's I've been struggling with them. So far, I've found a load that is borderline acceptable, but it's very sensitive to hold. A firm grip will shoot a low 8 when light group will shoot an x. Free recoil might be a 10 (though, I'm not sure which way as of yet - a very light hold shot better so I didn't really investigate).

I'm shooting a 32" barrel, and a 32" barrel is considerably less stiff than a 30" barrel, let alone a 28" barrel. This site has a very interesting calculator that can give you a good idea how barrel geometry impacts vibration: http://www.geoffrey-kolbe.com/articles/rimfire_accuracy/barrel_vibrations.htm It's a little obscure to use, but there is a big difference between lengths as the barrels get long.

The mathematical model used is not detailed enough to be take-it-to-the-bank accurate, but it can provide a useful comparison between, say 32", 30", and 28". In theory. Any one have any experience in this area? Anyone shooting 215's out of a 28" barrel and not finding vertical to be a problem?

I feel like I might solve a few problems by chopping 4" off my barrel. Which makes me wonder if 215's aren't the answer and I shouldn't be so stubborn.

 

[Steveb]

Interesting conversation. I tried these bullets when they first came out and found them to be somewhat unstable in the lower wind conditions from 2 - 7 MPH. When I shot 210 VLD's I would consistently get great groups from 300 to 1000 yards but when I switched to the 215's I got very good groups at 300 - 400 but after that I had issues. I lost several matches simply due to lost points that I couldn't explain so I went to a mid range match one weekend and a long range match the next. I shot half the relay's with 210's and half the relay with 215's as the best comparison I could get. This gave me about 14 relays to check them each against. In no relay did the 215 equal the accuracy of the 210's. I quit using the 215's.

I talked to Brian about this several times and really didn't get an answer but I find it interesting that people are now describing the issues I had several years ago in my rifles.

 

[Steveb]

In answer to the vertical question. I never found a vertical problem but simply the bullet groups were always somewhat bigger but more important I felt I simply couldn't drive them correctly. With the 210's I could tell which side of the X ring I could put it at 1000 on demand but with the 215's all I could do is say I would hit the 10 ring somewhere and if I centered the group I could get a good score but where the bullets were going to land I couldn't say.

 

[broncman]

My theory is barrel dwell time vs recoil. In other words, recoil actually starts before the bullet exits the barrel. I do have access to a ultra high speed camera but have not had time to shoot the videos. Thus a 32" has more movement before bullet exits barrel. My theory any way...

I only shot one 1000 yard relay with the 215's and posted a very good score. I must say that my hold and technique have evolved a lot since I first tried the 215's and sold what full boxes I had left.

I had no vertical issues that relay. I do not bag squeeze and I firmly bed the buttstock in the rear bag. My bag set directly on the he ground and I lay my cheek on the rest like a pillow. If my cross hairs are moving around I am not positioned right. I can typically stay in the black during recoil and usually just a slight push forward gets me right back.

It used to jump over to the side and I would have to reset everything..

 

[Hillhunter]

i tried different positions/holds last weekend with the 215,'s and found that my rifle prefers a slight to no hold, yes it jumps to the side and i have to reset everything but my verticals are now to a minimum, this is in a 32 inch 1/10 maybe the shorter barrel as other members have said might be better.