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20 Practical 9 twist 55 Berger Varmint bullets

lgwatson

Silver $$ Contributor
I'm having a 20 Practical bolt action with a 26 inch barrel built. I have a 9 twist barrel. Want to shoot 55 and 40 Berger Varmint bullets. My shooting will primarily be PDs at about 3400 to 3600 altitude. Any advice on load data or experience with those bullets would be appreciated. Berger stability tables indicate marginal stability with the 55s. I have seen some information the some people are shooting the 55s in a 9 twist.
 
I'm having a 20 Practical bolt action with a 26 inch barrel built. I have a 9 twist barrel. Want to shoot 55 and 40 Berger Varmint bullets. My shooting will primarily be PDs at about 3400 to 3600 altitude. Any advice on load data or experience with those bullets would be appreciated. Berger stability tables indicate marginal stability with the 55s. I have seen some information the some people are shooting the 55s in a 9 twist.
I also order an 8 twist barrel in case the 9 twist doesn't work out.
 
Use the search theres a $hit ton of info on 20 cals and 55's..
My info fireforming brass with my 20BRA and a 9tw input into Bergers twist calculator says my S.G is 1.26 and this is how it shoots I guess this will work
 

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I'm having a 20 Practical bolt action with a 26 inch barrel built. I have a 9 twist barrel. Want to shoot 55 and 40 Berger Varmint bullets. My shooting will primarily be PDs at about 3400 to 3600 altitude. Any advice on load data or experience with those bullets would be appreciated. Berger stability tables indicate marginal stability with the 55s. I have seen some information the some people are shooting the 55s in a 9 twist.
Hi this is my first post, so go easy on me.
I have a Titan running at 3000 fps using 55 Bergers, and at that speed Berger recommend a 1 in 8 or better, I run a 1 in 7 for the 55 Bergers and are getting good results.
Please be aware that there are two conflicting recommendations of twist rates published for Berger, you must find the most up to date data, as their research on twist rates was revised later on because they were having issues in some situations.

Some suggestions of speeds obtainable are just not achievable, so the slower twist they suggested therefore is not relevant, as you may know twist rates are quite dependent on the speed, and the speeds quoted are not achievable even with a 27" barrel, at sea level, as the pressures at those speeds exceed the capacity of the brass.
Mike 527.
 
Hi this is my first post, so go easy on me.
I have a Titan running at 3000 fps using 55 Bergers, and at that speed Berger recommend a 1 in 8 or better, I run a 1 in 7 for the 55 Bergers and are getting good results.
Please be aware that there are two conflicting recommendations of twist rates published for Berger, you must find the most up to date data, as their research on twist rates was revised later on because they were having issues in some situations.

Some suggestions of speeds obtainable are just not achievable, so the slower twist they suggested therefore is not relevant, as you may know twist rates are quite dependent on the speed, and the speeds quoted are not achievable even with a 27" barrel, at sea level, as the pressures at those speeds exceed the capacity of the brass.
Mike 527.
You are correct , Mike.. your about to the top of your Titan velocity , I suspect 3200fps is goon be hard on the brass, use a 100+% case fill powder.. I suspect the SP brass will handle the pressure a little better..

I’ll have my 20PPCAI reamers before long, I hope to achieve the 3000 mark w/ the 55gr. Although hopefully I’ll be using a 1-8” barrel.. mainly for the 40gr bullets..
 
806

Looks like you got yourself a heck of a shooter.
Tell us a little more about your rile and load. Any pictures?

Hal
 
Several years ago, I found a couple of 1-9tw 20 cal blanks on Bartlein's inventory list, and bought both of them. Put one on a Howa Mini action & the other on a M700, both chambered with my 20 Tactical reamer. I can get right around 3200fps with the 55s out of the 27" bbl on the M700 with H4895, and have seen some pretty decent 600yd groups out of it. Elevation here is 2600'-2800' MSL, and with the accuracy I'm seeing with 55s, I'm not looking to go with a faster-twist bbl for 20 cal rifles at this point.
Both rifles also shoot great with 32-40gr bullets, so overall, I'm happy with the 1-9s.
 
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I have a 1-10 twist 26" barrel in 20 Practical, and for 40 grain Hornady Vmax or Nosler 40 BT I have had good accuracy with 8208 XBR 24.9 grains, average about 3750 fps. My altitude is around 4000 - 4500 feet here. Use it for sage rats.

Have not tried anything above 40 grain in my 20P. Use my 20 Vartarg with 32 grain, and would likely go to a .223 / 5.56 for 55 grain bullet weight, I'm curious about what results you get with those 55 Berger varmint.

If you're looking for more options on powders for a 40 grain, IMR or H 4198, H335, LT-32, N133, IMR 4895. There is a lot on here about loads and what people like.
 
The 20 calibers have become my favorite. I've used the 20 VT for many years now and recently decided to do a 20 Practical. I built the 20 P for the 40 gr VMax, but it shoots the 32 gr Vmax faster and a little more accurate. The 20 VT is built on a Remington 700 with a 15" barrel and the 20 P is built on a Savage 110 action. To see more on the Savage you can go to this link. The 20 P 32 grs are running at 3650 FPS and the 40 grs are running 3245 FPS in the Savage.
IMG_0854.jpg
 
Not me. Honestly I believe a larger case is needed to give the 55’s a fighting chance.
I do to Tommie just couldn't remember what member on here has a 20VT shooting 55's.
Its Evan I believe coming back to me know.
 
There is nothing wrong with throwing a heavy bullet like the Berger 55 at slower speeds.

When you push them with 223/556 cases or 204 Ruger cases, you will just be slower than the same cases pushing the Seirra 39 or Hornady 40.

If someone wants to run the 55 out of a 223/556 or 204 Ruger variant, then they should go for it cause life can be short and if it makes them happy, why not.

If for a moment, we say that a typical 204 Ruger will produce roughly 1300 ft*lbs pushing a 40 gr, and we estimate the speed of the 55 grain at that energy, we would get roughly 3260 fps.

I have seen folks get their 55s up to just under that 3260 fps estimate in their 20P and 204 R cases.

If we check the trajectory of the 55 grain at 3260 fps, and compare it to the 40 grain at 3850, it tells a story.

If you try to look at where the 55 grain will show a significant advantage in terms of downrange trajectory, it takes roughly 3600 fps or more to make it shine. That is roughly 1583 ft*lbs in terms of the energy required from the cartridge, or in other words well above any 223 or 204 Ruger case at normal pressure.

For perspective, a 6 Dahser pushing a 105 at 2850 fps produces roughly 1893 ft*lbs.

A 22-250 pushing a 40 gr at 4224 fps is producing 1585 ft*lbs, same 22-250 using 55 gr at 3786 fps is producing 1751 ft*lbs.

We already mentioned, not everyone cares if their heavier bullets have a "better" trajectory and there is no law that says you cannot throw heavy bullets slower and still be happy.

A user still has to consider the appropriate twist needed for a 55 grain versus a 39 or 40 grain and what that means when/if used with the lighter bullets.

Here is a comparison of the typical energy levels with the 20 cal 40 VMax compared to a 55 Berger at 600 and 400 yards.
G7 BC Berger 55 Varmint BT = 0.182
G7 BC Honrady 40 VMax = 0.116

1738022551080.png
1738024312853.png
 

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