Load data info help

[Kramerica]

Got a 6.5 Grendel, and a lot of IMR 8208 XBR I’d like to use. Going with a Hornady 123SST. Hornady doesn’t show the 123SST with 8208 in their manual. Hodgdon has 123 SIE HPBT with 8208 but not the 123SST. Could I use the Hodgdon load data to work my load up?

 

[6.5grendel]

Is this an ar or bolt action? In an ar the max for most 123 gr bullets is 28.5 of 8208xbr. 8208 spikes in pressure really quick with the 120-123 class bullets. Like always start low and work up and pay close attention for signs of pressure when getting close to 28.5. Mine started showing pressure right at 28.5 so I backed down to right around 28.0 for the 123sst. Again, that is for an ar. I dont have any experience with the grendel in a bolt action so not can't give advice on that.

 

[Kramerica]

Is this an ar or bolt action? In an ar the max for most 123 gr bullets is 28.5 of 8208xbr. 8208 spikes in pressure really quick with the 120-123 class bullets. Like always start low and work up and pay close attention for signs of pressure when getting close to 28.5. Mine started showing pressure right at 28.5 so I backed down to right around 28.0 for the 123sst. Again, that is for an ar. I dont have any experience with the grendel in a bolt action so not can't give advice on that.

Yeah it’s for a Bolt, thank you though

 

[Bill K]

Hornady's Data loading site, shows start of 25.5 to a max of 28.5 with 8208..and the 123 grain bullet. Should be save to start with the 25.5 or 25.0 and work up. You could call Hornady tech and see what they say.

 

[Lone Hunter]

I will have to dig out my load data but I load for an AR with Hornady brass and a Howa Mini Action with Lapua brass. I use 123 gr Hornady ELD M in both weapons with IMR 8208 XBR with good results. The AR has a BHW barrel on it and shoots better than the Howa. I have not pillar bedded or skim bedded the Howa yet except to put it in a Boyd's AT-1 stock. I use 85 gr Sierra HP with very good accuracy but use H335 powder. The 8208 loads are no where near max. Too many projects. Will look for my data and check back in. Seating depth helped a lot also.

 

[Kramerica]

Hornady's Data loading site, shows start of 25.5 to a max of 28.5 with 8208..and the 123 grain bullet. Should be save to start with the 25.5 or 25.0 and work up. You could call Hornady tech and see what they say.

I was thinking about starting at 26.5 and working up. I did some load work with some 130’s and 8208 and had no pressure signs at max. I know it’s a different bullet but I think I’d be safe starting a little above the minimum, if I’m wrong feel free to correct me

 

[6.5grendel]

Also, the OAL for the 123's in an AR is usually around 2.26 max. Thats what length I run them at. I don't know what length you are able to load them in your bolt gun but if its considerably longer than 2.26 then that might lower the pressure.

 

[Steve Ladino]

Got a 6.5 Grendel, and a lot of IMR 8208 XBR I’d like to use. Going with a Hornady 123SST. Hornady doesn’t show the 123SST with 8208 in their manual. Hodgdon has 123 SIE HPBT with 8208 but not the 123SST. Could I use the Hodgdon load data to work my load up?

I use 29.2 grains of 8208 with the Hornady 123's in my Ruger predator Bolt action, pretty fast and very accurate. Measure the shank length of the SMK's vs the others . More length equals less powder.

 

[Kramerica]

I use 29.2 grains of 8208 with the Hornady 123's in my Ruger predator Bolt action, pretty fast and very accurate. Measure the shank length of the SMK's vs the others . More length equals less powder.

28.5 is at case capacity I believe.

 

[Kramerica]

Also, the OAL for the 123's in an AR is usually around 2.26 max. Thats what length I run them at. I don't know what length you are able to load them in your bolt gun but if its considerably longer than 2.26 then that might lower the pressure.

2.315” is mag length and I’m still jumping 0.040” when loaded at mag length

 

[jonbearman]

You could call the folks who rep the 8208. Now one knows more than the powder manufacturer.

 

[Steve Ladino]

28.5 is at case capacity I believe.

how is that achieved ?

 

[Straightshooter1]

Got a 6.5 Grendel, and a lot of IMR 8208 XBR I’d like to use. Going with a Hornady 123SST. Hornady doesn’t show the 123SST with 8208 in their manual. Hodgdon has 123 SIE HPBT with 8208 but not the 123SST. Could I use the Hodgdon load data to work my load up?

OK, so . . . putting this info into QuickLoad for a 6.5 Grendel (SAAMI) and here's what I'm seeing:

COAL set at mag length: 2.315
SAAMI max PSI is 52,000
Case Volume at 37.50 gr H2O (could be more or less depending on who's brass you're using)
29.05 gr of 8208 XBR fills the case to 100% and producing an estimated pressure of 58,590 psi (SAAMI max at 52,000)
28.0 gr of 8208 XBR fills the case to 96.4% and pressure at 52,429 psi
25.0 gr of 8208 XBR fills the case to 86.1% and pressure at 38192 psi

Where to start??? Well, 25.0 grs is plenty safe with the bullet seated out to mag length (even kinda light). Just keep in mind that as you shorten that seating depth, decreasing volume increases pressure. Fore example, seating to SAAMI spec of 2.260" with 25.0 grs of 8208 XBR increases the pressure to 39,828 (still, a little on the light side).

At mag length, you might find a node around 26.5 grs seating at mag length. At SAMMI spec seating, you might find the node around 26.1 grs. . . depending on the length of your barrel.

Hope this helps give you some ideas where to start and what to expect from this powder for this bullet.

 

[Kramerica]

OK, so . . . putting this info into QuickLoad for a 6.5 Grendel (SAAMI) and here's what I'm seeing:

COAL set at mag length: 2.315
SAAMI max PSI is 52,000
Case Volume at 37.50 gr H2O (could be more or less depending on who's brass you're using)
29.05 gr of 8208 XBR fills the case to 100% and producing an estimated pressure of 58,590 psi (SAAMI max at 52,000)
28.0 gr of 8208 XBR fills the case to 96.4% and pressure at 52,429 psi
25.0 gr of 8208 XBR fills the case to 86.1% and pressure at 38192 psi

Where to start??? Well, 25.0 grs is plenty safe with the bullet seated out to mag length (even kinda light). Just keep in mind that as you shorten that seating depth, decreasing volume increases pressure. Fore example, seating to SAAMI spec of 2.260" with 25.0 grs of 8208 XBR increases the pressure to 39,828 (still, a little on the light side).

At mag length, you might find a node around 26.5 grs seating at mag length. At SAMMI spec seating, you might find the node around 26.1 grs. . . depending on the length of your barrel.

Hope this helps give you some ideas where to start and what to expect from this powder for this bullet.

Thanks you. Using Starline brass. 22” Barrel. I shot the loads the other day from 26.9 to 28.5. My best load was 28.1 as far as grouping goes (.36Vertical average at 100 yards) and I got 2476FPS. Brass/primers showed no pressure signs even at 28.5gr but from your numbers it sounds like I may be right at or a touch over pressure according to SAAMI

 

[Kramerica]

how is that achieved ?

That’s what the manual said that a friend sent me the other day. 28.5 was at case capacity without crushing the bullet into the powder.

 

[Straightshooter1]

Thanks you. Using Starline brass. 22” Barrel. I shot the loads the other day from 26.9 to 28.5. My best load was 28.1 as far as grouping goes (.36Vertical average at 100 yards) and I got 2476FPS. Brass/primers showed no pressure signs even at 28.5gr but from your numbers it sounds like I may be right at or a touch over pressure according to SAAMI

If that MV is somewhat accurate, it seems you're well below the SAAMI pressure limit using the 28.1 grs at your mag length (assuming a temp of 60°F). And from what I can see, getting into higher summer temps (like 90's), this load should still be OK . . . but, I'd keep an eye out for pressure signs until tested at those temps.

I've not used or measured an Starline brass for case capacity and haven't heard how it might compare to others. So . . .??? So, I'm just using what QuickLoad uses as the standard. It's showing case capacity of 37.5 gr H20 and with that load of 28.1gr at mag length, the case is filled to 96.7%.

Good luck, good shooting!

 

[Steve Ladino]

That’s what the manual said that a friend sent me the other day. 28.5 was at case capacity without crushing the bullet into the powder.

It doesn't hurt to seat a long bullet into the powder itself. This is usually what I end up doing with factory rifles as they are throated shorter than ideal for longer bullets and maximum powder charges. The maximum charges listed in reloading manuals are maximum SAFE quantity's. Often I go over the listed safe maximum amounts, not by much usually, but at times a grain or two depending on which caliber and bullet I'm working with, carefully checking pressure signs as I go in bolt action actions. My best groups are near or over max charges as long as the burn rate of the powder is appropriate for the barrel length and caliber. I have seen that 28,5 grains of 8208 XBR is a very popular amount. If that works for you then that's great.
To avoid crushing powder use a drop tube or seat the bullet ( Boat Tail type ) to the powder level then remove the cartridge and tap the bullet point easily on the bench , reinsert the cartridge into the seating device and finish seating, then re check length.
In addition I might add that I load one at a time often .010 " off the lands.

 

[best defense]

I could be wrong but as I understand the load books, the load recomendations are for bullet weight, not for bullet brand and small differences between the type of bullet are not taken into account when recomending a powder charge.