.233 or .253 Freebore?

[jrod1101]

New to the FTR game and new to 308 Win. I primarily been shooting 6.5 x 47 Lapua in a Silhouette Rifle out 500 meters. I purchased a rifle that has the following chamber and was advised that it is ready for heavy bullets. I plan to begin reloading for this rifle is the freebore .233 or .253? Does anyone know if 185 Juggs would work in that much freebore for Mid-Range and 200-20X for Long Range? Any information is greatly appreciated as I have not seen much information on this much freebore.

Thanks,
Jimmy

 

[Bart B.]

Freebore is .233" but I don't know that bullet's shape details.

What's does "200-20X" mean besides a perfect clean on NRA targets?

 

[Dos XX]

A 185 Juggernaut will still be in the neck. I have a .170 fb chamber. I held a loose bullet next to one of my seated rounds and moved it up an eyeballed .063 using a caliper for reference, and it looks to be a little over half way up the neck. It isn't a totally precise way to do it.

A 200 Hybrid should work in that chamber.

I don't have any 200-20x bullets to look at.

 

[jrod1101]

Freebore is .233" but I don't know that bullet's shape details.

What's does "200-20X" mean besides a perfect clean on NRA targets?

This is a Target Bullet made by Berger Bullets / .30 Cal 200.20X gr Hybrid Target
http://www.bergerbullets.com/200-20x-perfect-bullet-f-tr/

 

[jrod1101]

A 185 Juggernaut will still be in the neck. I have a .170 fb chamber. I held a loose bullet next to one of my seated rounds and moved it up an eyeballed .063 using a caliper for reference, and it looks to be a little over half way up the neck. It isn't a totally precise way to do it.

A 200 Hybrid should work in that chamber.

I don't have any 200-20x bullets to look at.

Dos XX,

Thank you very much for the information, I appreciate it!!!! I believe the 200-20X have just a bit more bearing space than the Hybrid Target. It sounds like 200gr will be the starting point. Thanks again!

 

[Ned Ludd]

For 185 Juggernauts, .140"-.170" freebore will be optimal. You can load them at .015" off in a chamber with as little as .085" freebore and still keep the boattail/bearing surface junction above the neck/shoulder junction. However, that is not optimal an will require much higher than necessary pressure for a given velocity. I'm running a .180" freebore chamber with both 185 Hybrids and 200.20Xs. IMO, it would be just a bit too long for the Juggernaut. The .170" freebore FTR reamer many have been using is just a bout perfect and will allow you to load 185s (Juggernauts or Hybrids) and 200s (Hybrids or 20Xs). If you have any plan to run the 200s, get a yourself 10-twist barrel, which will also work well with the 185s. You can also use an 11-twist for 185s, but will be under-spinning the 200s. So in both cases (freebore and twist rate), I would suggest using a parameter that will allow you to optimally run any of the 185/200 gr bullets. The .170" fb and 10-twist barrel will do that.

The .233" freebore in your reamer print may well have been set up for the Berger 215 Hybrids. Although you can use a 10-twist barrel, the 215s might do better with a 9.75 twist to get the full BC. You might be able to physically load rounds with the 200 Hybrids or 200.20X bullets, but the bullets will have very little shank gripped by the case neck. The Juggernaut shank would be just barely in the neck, or possibly even completely out seated at touching to about .020" off. You could try jumping them a much longer distance than the typical .015" to .030" most people find to be optimal. The Jug is very tolerant of seating depth. However, the easiest thing is simply to use the bullet the freebore was designed for.

One of my .308 F-TR rifles has .180" fb. In that rifle, the 200.20Xs seated at ~.012" off the lands puts the boattail/bearing surface junction very close to halfway out the neck. You might be able to seat them at the same depth with another .053" of freebore (.233" freebore), but they're going to be pretty far out in the neck. If you decide to go this route, you might want to try a bushing .001" smaller than you would ordinarily use to put a little more tension on the bullets when they're seated out that far. In any event, you have a few choices, but the Juggernaut is probably not the best choice with that throat.

 

[T-shooter]

For 185 Juggernauts, .140"-.170" freebore will be optimal. You can load them at .015" off in a chamber with as little as .085" freebore and still keep the boattail/bearing surface junction above the neck/shoulder junction. However, that is not optimal an will require much higher than necessary pressure for a given velocity. I'm running a .180" freebore chamber with both 185 Hybrids and 200.20Xs. IMO, it would be just a bit too long for the Juggernaut. The .170" freebore FTR reamer many have been using is just a bout perfect and will allow you to load 185s (Juggernauts or Hybrids) and 200s (Hybrids or 20Xs). If you have any plan to run the 200s, get a yourself 10-twist barrel, which will also work well with the 185s. You can also use an 11-twist for 185s, but will be under-spinning the 200s. So in both cases (freebore and twist rate), I would suggest using a parameter that will allow you to optimally run any of the 185/200 gr bullets. The .170" fb and 10-twist barrel will do that.

The .233" freebore in your reamer print may well have been set up for the Berger 215 Hybrids. Although you can use a 10-twist barrel, the 215s might do better with a 9.75 twist to get the full BC. You might be able to physically load rounds with the 200 Hybrids or 200.20X bullets, but the bullets will have very little shank gripped by the case neck. The Juggernaut shank would be just barely in the neck, or possibly even completely out seated at touching to about .020" off. You could try jumping them a much longer distance than the typical .015" to .030" most people find to be optimal. The Jug is very tolerant of seating depth. However, the easiest thing is simply to use the bullet the freebore was designed for.

One of my .308 F-TR rifles has .180" fb. In that rifle, the 200.20Xs seated at ~.012" off the lands puts the boattail/bearing surface junction very close to halfway out the neck. You might be able to seat them at the same depth with another .053" of freebore (.233" freebore), but they're going to be pretty far out in the neck. If you decide to go this route, you might want to try a bushing .001" smaller than you would ordinarily use to put a little more tension on the bullets when they're seated out that far. In any event, you have a few choices, but the Juggernaut is probably not the best choice with that throat.

How fast are you pushing the 200.20X's? I don't shoot competition but a bullet that had worked for me for out to 500 yards is the Hornady 208g A'Max or ELD Match. I've never worked up a load for accuracy with these but loaded them reasonably hot for distance. They have shot to 1/2 MOA at 500 yards. The bullet is long which will restrict the powder load in a standard chamber, with a lot of bearing surface remaining behind the neck when loaded to 2.972" (pictured below) giving me .025" jump.

 

[Ned Ludd]

I'm running the 200.20Xs at ~2660 fps with H4895 out of a 30" barrel. There are a couple major differences between the 200.20X and the Hornady offerings you mentioned. First, they are secant ogive bullets, which may mean their seating depth preferences could differ from that of the 200.20X or 200 Hybrid, which have Hybrid ogives. Second, the Hornady bullets have longer bearing surfaces as compared to the 200.20X, which may affect velocity and will usually mean that you have more shank in the neck and/or down in the case at a given seating depth. Neither of those differences are deal-breakers in any way, just differences.

In the image you posted, the boattail/bearing surface junction of the bullet [as seated] is below the case shoulder. That means you are giving up considerable effective case volume to the boattail/shank of the bullet, producing higher pressure at a given velocity, or limiting the velocity you can reasonably attain at a given pressure. My 200.20X load in the .180" freebore chamber has a COAL of 3.114", which puts the boattail/bearing surface junction slightly below halfway out the neck (see image below). If you were to seat the 208s any deeper in the case, you might even reach a point where the pressure ring of the bullet bearing surface is below the lowest point sized on the neck by a standard bushing die. In fact, you may be there already. That may work ok, but is not optimal. I'm guessing you'd be getting somewhere in the neighborhood 2475-2550 fps with the 208 loaded in that manner. Again, it may work ok, but it's not what you could be getting with a more optimal freebore that allowed to seat them out substantially farther.

 

[T-shooter]

I'm running the 200.20Xs at ~2660 fps with H4895 out of a 30" barrel. There are a couple major differences between the 200.20X and the Hornady offerings you mentioned. First, they are secant ogive bullets, which may mean their seating depth preferences could differ from that of the 200.20X or 200 Hybrid, which have Hybrid ogives. Second, the Hornady bullets have longer bearing surfaces as compared to the 200.20X, which may affect velocity and will usually mean that you have more shank in the neck and/or down in the case at a given seating depth. Neither of those differences are deal-breakers in any way, just differences.

In the image you posted, the boattail/bearing surface junction of the bullet [as seated] is below the case shoulder. That means you are giving up considerable effective case volume to the boattail/shank of the bullet, producing higher pressure at a given velocity, or limiting the velocity you can reasonably attain at a given pressure. My 200.20X load in the .180" freebore chamber has a COAL of 3.114", which puts the boattail/bearing surface junction slightly below halfway out the neck (see image below). If you were to seat the 208s any deeper in the case, you might even reach a point where the pressure ring of the bullet bearing surface is below the lowest point sized on the neck by a standard bushing die. In fact, you may be there already. That may work ok, but is not optimal. I'm guessing you'd be getting somewhere in the neighborhood 2475-2550 fps with the 208 loaded in that manner. Again, it may work ok, but it's not what you could be getting with a more optimal freebore that allowed to seat them out substantially farther.

Thanks for the reply. I run 41.5 grains of Varget for an average of 2,430 fps. I haven't got to shoot at that distance but it should be stable out to about 1,000 yards staying above mach 1.2 in warmer weather. I ordered a box of 175g Sierra Match Kings to experiment with and I may try some of the bullets you use.

 

[Ned Ludd]

You might want to give the Berger 185 Juggernaut or 175 OTM Match bullets a try. Both have significantly better BCs than the SMK 175, but don't require nearly the amount of freebore necessary to loadf the 208s optimally.

 

[jrod1101]

gstaylorg,

Thank you for sharing your information, I appreciate it! I am going to try 200gr in 20x and/or Hybrid. There are 210 Target and 215 Hybrid as you mentioned even the 230 but I think that is very extreme for 308. My barrel is a brux 1:10 32" barrel. This might be a long range only setup and I might have to just make a mid range rifle to match with .180 freebore for the 185 - 200 gr bullets. Attached is great information on Berger bullets for dimensions, I wish others would post their dimensions like Berger does.

[/URL]

[/URL]

 

[Ned Ludd]

I went with the .180" freebore for a very specific reason. However, there are quite a few using .170" freebore as cut by the shorter throat version of the FTR reamer with great success. It seems as though a number of smiths around the country have access to this reamer. The .170" freebore will work well with 185 Jugs or Hybrids, as well as 200 Hybrids or 200.20X bullets. It's a very good all-around throat length for bullets in that length (weight) range. If you desire to lengthen your existing freebore without having to re-barrel, the PTG (Pacific Tool and Gauge) Uni-Throater will do a great job:

http://pacifictoolandgauge.com/throat-and-neck-reamers/5226-17-cal-uni-throater-kit.html

 

[XTR]

The 200-20x has barely any bearing surface in the case with a .205 freebore. You will not be able to reach the lands with a .233; should be the same for the 185 Jugg.

As Greg noted above, that .233 freebore print would be for shooting the 215Hybrids.

I don't think that you will be able to reach the lands with a 200Hybrid, it would be really close at .233

Unless you plan to shoot the 215H exclusively in that barrel I'd find a PTG FTR reamer and have it set back 2 inches. (my testing shows less than 25FPS difference in a 32 and a 30 with identical loads) Either of the PTG designs with the .168 or the .170 FB will be great; or if you are buying a reamer I might get something with about a 180. That would be good for the 185 or any of the 200s.

 

[Joe Wade]

Jimmy, you might have trouble making weight (18.2lbs) with that heavy contoured 32" barrel for F-tr.

 

[jrod1101]

Thank you everyone for the great information.... Very informative post for me!

 

[T-shooter]

I'm running the 200.20Xs at ~2660 fps with H4895 out of a 30" barrel. There are a couple major differences between the 200.20X and the Hornady offerings you mentioned. First, they are secant ogive bullets, which may mean their seating depth preferences could differ from that of the 200.20X or 200 Hybrid, which have Hybrid ogives. Second, the Hornady bullets have longer bearing surfaces as compared to the 200.20X, which may affect velocity and will usually mean that you have more shank in the neck and/or down in the case at a given seating depth. Neither of those differences are deal-breakers in any way, just differences.

In the image you posted, the boattail/bearing surface junction of the bullet [as seated] is below the case shoulder. That means you are giving up considerable effective case volume to the boattail/shank of the bullet, producing higher pressure at a given velocity, or limiting the velocity you can reasonably attain at a given pressure. My 200.20X load in the .180" freebore chamber has a COAL of 3.114", which puts the boattail/bearing surface junction slightly below halfway out the neck (see image below). If you were to seat the 208s any deeper in the case, you might even reach a point where the pressure ring of the bullet bearing surface is below the lowest point sized on the neck by a standard bushing die. In fact, you may be there already. That may work ok, but is not optimal. I'm guessing you'd be getting somewhere in the neighborhood 2475-2550 fps with the 208 loaded in that manner. Again, it may work ok, but it's not what you could be getting with a more optimal freebore that allowed to seat them out substantially farther.

I canceled the Sierra order and ordered a box of the 200.20x. I don't have the freebore to seat them out as far as you do here and I seated them at .025" off the lands where everything else seems to shoot well. With the short bearing surface I still have about 80% contact in the neck. I also remeasured the Hornady ELD in the chamber. I think the other picture I posted was wrong as it looked like the bullet was seated too deep. I have no idea, that was a couple years ago. I'm going to start with the load I used with the ELD and work up in 2/10 increments. Hope to see above 2,500 fps, the ELD is maxed out at 2,430 with a slightly compressed load of Varget. If anyone had too much freebore and need to seat out farther, the Hornady would work and keep more contact in the neck. I noticed that when using the Hornady comparator, these seat .010" farther out than the ELD's to keep the same jump distance. That tool measures .298" inside. Also these Berger bullets are more touchy to measure in the chamber. The slightest bump or pressure will push them .010"-.015" or more into the rifling and give a false reading. I used 3 different bullets to be sure I was getting the right measurement and not altering the surface.

 

[Ned Ludd]

It looks like the 200.20X is seated more optimally in the neck compared to Hornady bullet with its longer bearing surface. The longer and "pointier" the bullet ogive, the more sensitive it will be to accidentally being pushed into the lands when using the Hornady OAL gauge. A little practice with the tool is usually sufficient to develop a good feel for the difference between just barely touching, or .010" into the lands. As you noted, it's alway a good idea to check for land engravement as well. I typically select 10 bullets at random from a new Lot, number them with a Sharpie, and use them as a measurement "set" to periodically measure the distance to the lands as long as I'm shooting that specific Lot of bullets. I use the average of 10 measurements as the baseline for seating depth. It's not perfect, being a "relative" measurement, but I rarely observe variance greater than about 1.0 to 1.5 thousandths over the 10 measurements. Because I rarely, if ever, start seating depth tests with the bullet closer than about 3 thousandths from "touching", it works well enough to establish a baseline reference measurement. In any event, let us know how the 200.20Xs work out for you. Good luck!

 

[T-shooter]

It looks like the 200.20X is seated more optimally in the neck compared to Hornady bullet with its longer bearing surface. The longer and "pointier" the bullet ogive, the more sensitive it will be to accidentally being pushed into the lands when using the Hornady OAL gauge. A little practice with the tool is usually sufficient to develop a good feel for the difference between just barely touching, or .010" into the lands. As you noted, it's alway a good idea to check for land engravement as well. I typically select 10 bullets at random from a new Lot, number them with a Sharpie, and use them as a measurement "set" to periodically measure the distance to the lands as long as I'm shooting that specific Lot of bullets. I use the average of 10 measurements as the baseline for seating depth. It's not perfect, being a "relative" measurement, but I rarely observe variance greater than about 1.0 to 1.5 thousandths over the 10 measurements. Because I rarely, if ever, start seating depth tests with the bullet closer than about 3 thousandths from "touching", it works well enough to establish a baseline reference measurement. In any event, let us know how the 200.20Xs work out for you. Good luck!

Thanks. As soon as the wind stops blowing so hard, I'll test them. Right now it's a constant 25 mph with rain due in tonight.

 

[Crow]

tag