My results with CFE223 and 8208XBR

[JPShooter]

Hey guys,

I'm new here (see my first Grendel rig here: http://www.65grendel.com/forum/showt...My-New-Grendel!)

I posted in that thread regarding my initial findings with the Hornady Factory loading in 123 SST's.

I've tried using some H335 that I have a great deal of, but it did not get me the velocity that I was hoping for without pressure signs.

I then did a little testing here at the house with some CFE223 just checking for velocity vs. pressure signs (no accuracy shooting as I do not have a range, but can shoot on my property). What I saw was giving me much hope, but it turned out that once I loaded up 5 round groups and headed to the range the ES's were far too high and the accuracy was dismal for me.

However, 8208XBR has turned out to be another story for me!

Here's the details:

Lapua new brass neck sized with a .287 sleeve in a Redding Die.
Hornady 123 gr SST's
CCI450's
2.712 OAL with Hornady Comparator (Matching my reading for Factory 123 SST Loads)

I again went through the process of checking various loads at the house for pressure signs and velocity, then loaded up 5 of each at 28.2/28.4/28.6 grains and went to the range to see what these would look like as far as ES's and grouping.

It seems that this rifle (20" Shilen barrel) really likes the 28.4 grain load. That's a .45 inch 5 shot group, with an ES of 10 and an average velocity of 2489 FPS. I would like a little faster, but accuracy over velocity!

It's interesting how the groups opened up both above and below by .2 grains.

I am going to try now and experiment with seating depth variations and this 28.4 grain load. My chamber will take another .016 before I hit the lands, and that load will fit in my ACS mags from AA. I'm not going to push it any closer than .005 from max length to leave a little margin for any shifting that might take place in a worst case scenario. If anyone has any wisdom in that regard I'm all ears.

Thanks for looking!
Jake

[bwaites]

2.712? are you sure? Max mag length is 2.26.

Great shooting!

[JPShooter]

That's the measurement using one of these gizmos.

Not my picture, just pulled it off the web.

[37L1]

Did you subtract the length of the comparator holder from the final read out?

[1911man]

Thanks for sharing your results JPshooter. What you have shared looks very similar to what I have read from other people and my own experience with XBR. My rifle actually shoots 28.3-28.5 really well with a 120 smk but my ES is tightest with 28.3 grains at 7 fps (2450 fps average). I had the same problems with CFE 223, I have not been able to find a load that will group at all with it but I badly want to achieve the higher velocities it is capable of. My rifle also loves TAC and I have yet to find a charge of TAC with a 120 SMK that wont shoot sub MOA but again the velocities just arent there. On the plus side I just took my pet load of TAC (28.7 grains/120 SMK 2420 fps avg) out to the 600 yard line and I was easily hitting 5" steel varmint targets and making head shots on silhouettes with it so those lower velocities will still get the job done.

[JPShooter]

Did you subtract the length of the comparator holder from the final read out?

No, I did not. I actually am also using the incorrect insert

I've never bothered subtracting the inch for the holder and insert, and when I bought the set I only got the smaller selection of inserts. So I've been using the #4-25 when what I think is meant for the 6.5 is the #5-26, which I need to order. I really don't think it all makes much difference so long as all the numbers are relative, which they are to me.

It is however confusing for me to post those numbers here, and I apologize for that as I had totally forgotten that I was working that way.

[JPShooter]

Thanks for sharing your results JPshooter. What you have shared looks very similar to what I have read from other people and my own experience with XBR. ..................................

As your experience shows, the accuracy is more important than the velocity. But then we (I do) want it all and we want it now!

I am wondering if this being a new barrel will "speed up" as it breaks in? 2489 is not too bad, but the factory loads at 2570 (in my barrel) gives at least an additional 75 yards of effective range, and every little bit helps when we're dealing with a round at this velocity.

[Jakal]

My Lilja barrel shoots CFE great, my Bartlein does not like it, low speeds and not good accuracy, un-burnt powder. It does likes AR-Comp. and TAC though!

[JPShooter]

It's really amazing how much variance there is between barrels!

And it also makes me wonder how it is that manufacturers like Federal can come up with a load that shoots so well from so many different barrels. Look at Federal Gold Medal Match in .308, it shoots great out of most rifles. The factory Hornady 123 gr. SST's shoot well for many as well.

I read an article some time back that talked about the FGMM loads for .308 as being formulated to hit a velocity that puts it in a node range of the average barrel. But how they figure that out I have no idea.

[LR1955]

It's really amazing how much variance there is between barrels!

And it also makes me wonder how it is that manufacturers like Federal can come up with a load that shoots so well from so many different barrels. Look at Federal Gold Medal Match in .308, it shoots great out of most rifles. The factory Hornady 123 gr. SST's shoot well for many as well.

I read an article some time back that talked about the FGMM loads for .308 as being formulated to hit a velocity that puts it in a node range of the average barrel. But how they figure that out I have no idea.

JPS:

It is very easy to get a .308 to shoot very well using almost any safe load in almost any barrel. Even easier if you shoot a bullet with a tangent ogive. There is no magic to 41 grains of 4895 or similar powder and a 168 Match King.

The 6.5 mm twin is the 120 Match King. That's why I always recommend it for guys who think their barrel is giving them problems. A moderate load of a safe powder and a 120 Match King will most likely shoot well from any reasonably good 6.5 barrel.

However, I think the 123 SST's have a secant or a hybrid ogive. All bets are off in terms of the potential that a secant or hybrid ogive bullet will shoot well with many barrels.

LR55

[Jakal]

Well I have noticed a trend that others rifles here report the same as my Bartlein and not liking CFE. Seems if the barrel likes it, CFE shoots well.

[JPShooter]

JPS:

It is very easy to get a .308 to shoot very well using almost any safe load in almost any barrel. Even easier if you shoot a bullet with a tangent ogive. There is no magic to 41 grains of 4895 or similar powder and a 168 Match King.

The 6.5 mm twin is the 120 Match King. That's why I always recommend it for guys who think their barrel is giving them problems. A moderate load of a safe powder and a 120 Match King will most likely shoot well from any reasonably good 6.5 barrel.

However, I think the 123 SST's have a secant or a hybrid ogive. All bets are off in terms of the potential that a secant or hybrid ogive bullet will shoot well with many barrels.

LR55

Thanks for the insight, much appreciated!