22br 90gr Berger VLD - freebore and twist number needed

[savet06]

Thank you ahead of time for your information.
I have been reading as much as I can from past posts as well as the cartridge guide on this subject and have a good idea of numbers, but want to finalize my specs before I order the reamer and barrel. Will be for IBS competition shooting.

From what I have gathered 1:7 up to 1:7.5 twist barrels are ideal with the 22br velocities with maybe a 1:7.2 being perfect? This will be a button rifle barrel per request of the owner and a 1:7 is available from that particular maker...if we are leaving something significant on the table I will be happy to convince the owner of the rifle to go a different way.
Shooting will be done in temps above 60F for the most part, but not likely too far below that...highs in the 90's.

I will be ordering my reamer from JGS so a specific freebore length would be great. I know PTG has a reamer set up for this cartridge and 0.169 was listed a few times as well as up to 0.180-.185.
Thanks again,
Mike

 

[Evan]

Have you seen my info on the 22BR?

My new 22BR!

Hi Folks. I've been posting up questions revolving around the 22BR recently. http://forum.accurateshooter.com/threads/new-22br-coming-which-dies.3979615/ http://forum.accurateshooter.com/threads/are-the-90s-worth-it-in-a-22br.3977792/ I also posted up the new stock I made for my 22-250, which...

forum.accurateshooter.com

I wouldn't go that long a freebore. The 22BR has a way longer neck than a 223. The 0.100 freebore on my reamer was good. I also am skeptical of using a 7 twist again after my experience losing bullets constantly. I'd go as slow as I could: 7.5 or slower. My second barrel is a Krieger 7.7, but I haven't threaded it on yet.

 

[22BRGUY]

8208XBR is MAGIC! in my rifle

 

[Ned Ludd]

I would strongly recommend using a 0.219"/0.224" bore/groove barrel configuration. The 90 VLDs can be pushed to the point of jacket failures even with the relatively small .223 Rem case in 0.218" [tight] bore barrels, especially if twist rates faster than 1:7 are used. Think of how much more stress on the bullet jacket is possible with a 22BR case. You might mitigate some of that stress by going with a slower twist rate barrel (i.e. 1:7.2). However, using 0.219" bore barrel seems to be an even better preventative measure to minimize the risk of jacket failures.

 

[manitou210]

had this made by JSG IS HAD WORKED PERECT FOR 90 GR VLD, 80.5 BERGERS AND AMAZING THE 88 GR HOR
FIRED 15 SHOTS AT 900 METERS 12 IN V BULL 5" 3 IN BULL 10"
I ONLY USE JGS REAMERS

 

[savet06]

Thanks, guys, I will take it all under advisement and try to put the best combination together.
It seems like there are a lot of variables with this cartridge that need to be right to make it work well. Thank you for your time!
Mike

 

[PracticalTactical]

Thanks, guys, I will take it all under advisement and try to put the best combination together.
It seems like there are a lot of variables with this cartridge that need to be right to make it work well. Thank you for your time!
Mike

The best advice I can offer is to test seating a bullet in a case and make sure the base of the bearing surface is seated forward of the neck to shoulder corner. If you have a belt sander, (or maybe a Dremel) sand a case in half so you can see it for yourself.

This will ensure a number of things...

When a donut forms in that corner, and it will, the pressure will mess with your ability to control both seating depth and neck tension. You don't want that.

It also ensures the bearing surface of the bullet is protruding from the front of the case as much as possible... This is very important.... With high BC bullets like this, it is critical that the bullet enters the rifling along the same axis as the bore. Don't take this for granted. The more of the bearing surface that is exposed, the more of the diameter of the free bore can guide that bullet straight into your rifling.

Here's where things get interesting... Take a micrometer and measure the bearing surface of a bullet, then open up the micrometer by 0.0005" or 0.001" and examine the angular offset that becomes available as you open the mic. This will give you a sense of how loose a free bore diameter may be if you don't make efforts at the design stage to control it. It also gives you a sense of what is common and why so few shooters have great success pushing the limits of BC.

Since reamer manufacturers will work to a maximum material condition, you can be assured the free bore on your reamer will be considerably larger than that number on the reamer print.

Add to that, the engine lathe tail stock alignment error to the axis of the spindle. The farther out they extend that quill, they farther off the center of your reamer will drift off center. This will result in a trumpet mouth of the free bore.

This might seem like heady stuff to a non machinist, but certainly something you want to discuss and clarify with your pipe fitter before fitting your barrel. Using a CNC lathe is likely going to produce the most consistent result if the engine lathe operator is not top drawer.

Your free bore diameter needs to be every bit as small as it is safe to use to get best results with VLDs. This is in contrast to every fiber in the reamer manufacturers soul as he wants to give you an over size free bore.

Remember a reamer will always cut oversize.

As stated above, you want a good long free bore length exceeding 0.200" for 88s and 90s.

 

[Evan]

@savet06 I don't have an 90 VLD on hand, but here are a bunch of others I do with my 0.100 freebore 22BR:

Left to Right, 95 SMK, 90 SMK, 88 ELD, 85.5 LRHT, 80 VLD, 80 SMK each "seated to touch"

From my notes,and Berger's dimensions on the website you can put the 90 vld right next to the 88 ELD with the base of their boattails lined up.

 

[Ned Ludd]

@savet06 I don't have an 90 VLD on hand, but here are a bunch of others I do with my 0.100 freebore 22BR:
View attachment 1354672
Left to Right, 95 SMK, 90 SMK, 88 ELD, 85.5 LRHT, 80 VLD, 80 SMK each "seated to touch"

From my notes,and Berger's dimensions on the website you can put the 90 vld right next to the 88 ELD with the base of their boattails lined up.

They say a picture is worth 1000 words. That picture is worth about one million words. That's an outstanding lineup of bullets and the two cases for comparison!

 

[linebaugh]

Have you seen my info on the 22BR?

My new 22BR!

Hi Folks. I've been posting up questions revolving around the 22BR recently. http://forum.accurateshooter.com/threads/new-22br-coming-which-dies.3979615/ http://forum.accurateshooter.com/threads/are-the-90s-worth-it-in-a-22br.3977792/ I also posted up the new stock I made for my 22-250, which...

forum.accurateshooter.com

I wouldn't go that long a freebore. The 22BR has a way longer neck than a 223. The 0.100 freebore on my reamer was good. I also am skeptical of using a 7 twist again after my experience losing bullets constantly. I'd go as slow as I could: 7.5 or slower. My second barrel is a Krieger 7.7, but I haven't threaded it on yet.

I shot gobs of 88s 90s and 95s in 22250AI, 22BRI and 22GT. I am also skeptical of 7 twist anymore. The 7tw barrel I got the most rounds out of before beginning popping bullets had the .001 more bore diameter and made it near 2000 as i remember. I cant even remember whos barrel it was but probably bartlein or kreiger. I went to 1:8 twist after that. seems like 300,000 rpm is where things get shady.

I do have a 22250AI with a 7 twist that has got a lot of rounds on it and I cant remember popping bullets.

My experience was bergers are the most prone, 88 eld next and 90-95 smk the least prone to popping.

 

[urbanrifleman]

If I were doing a 22br for the Hornady 88 I would use about 150 fb at least.

I throated a customers 22250 for the 88 and it ended up about 170 to truly get clear of the donut.