LTR and 178 AMAX?

[Hunt]

I have predominantly shot SMKs out of this rig but have decided to switch over to AMAX for a change. I have loaded up charges of 44.0, 44.2 and 44.5 gr of Varget as these have been accurate loads in the past using CCI primers and Winchester brass. Velocity averages are 2507 (ES: 34, SD: 15) with the 44.0 gr and 2531 (ES: 26, SD: 9) for the 44.5 gr load. This was with a COAL of 2.842 and a comparator value of 2.214 to the ogive. This was too long for the BDL magbox so I need to drop back to 2.800.

Where I'm falling short is the fact that the ogive on the SMK and AMAX are different and the AMAX need to be seated deeper for similar ogive readings.

I have researched the loads section and have looked around the 'net to find what _MOST_ are using in their LTR as an OCW load. Some seem to think that 45.0 gr of Varget with a 175 SMK is the sweet spot. Will this load work with the 178 gr AMAX seated to 2.800? This seems like a lot of powder compression.

What are others running in their LTR/SPS Tac in terms of:

- # of gr Varget
- Brass
- OAL
- Primer
- Velocity/Extreme Spread

 

[Twitch2120]

Re: LTR and 178 AMAX?

im watching this closely...

 

[StockDog]

Re: LTR and 178 AMAX?

Tag

 

[Boomholzer]

Re: LTR and 178 AMAX?

Your Varget/AMAX velocity numbers look the same as what I found in my reloading log for LTR.
All-else-the same, your AMAX and SMK data should be really close.

I never had good performance with Varget, velocity wise, in short barrels. Log shows that velocity increase from 44gr on flattened out. I have since predominately run RE-15.

The jump or throat is long enough where the O-Give length is just a number for seating and case volume consistancy. If I rememeber correctly there is about a 0.05 difference in COAL. I have a drop-mag kit so i'm not as limited, although I don't recall the internal BDL box being that tight.

 

[RobG]

Re: LTR and 178 AMAX?

My .308 LTR is gone but, Alliant 2000mr gave me great results. 2650 fps, sd in the 9-10 range if I recall correctly. Varget and R15 gave unacceptable results in my gun. My load was 48 grains, book max, at 2.810, using a 210m primer in Win brass

 

[Gene Poole]

Re: LTR and 178 AMAX?

My experience with the two has been in a 24 inch R700 PSS (1:12) but the ballistics have been about identical out to 600 yards (max available at my range). I've even shot them interchangeably in an F-Class match where I ran out of one mid course.

Though the charge weight is the same (I use 44.5 Varget) the seating depth of the two can't be directly correlated. I did a seating depth workup for both bullets independently and my data are based on the Hornady ogive comparator and show the SMKs best at near spec COAL (2.802 - 2.805 depending on lot) and out a bit further on the A-Max bullets (2.898 - 2.905 depending on lot). Sorry, I don't have the actual ogive measurements handy for these. The A-Max bullets--even at this extended COAL--still sit a bit deeper into the case and compress the Varget slightly. With a drop tube, 44.5 gn Varget just fits with the 175 SMKs (in Lapua cases which tend to hold less than say Winchester brass).

I think it best to work these up youself rather than rely on others data.

 

[Hunt]

Re: LTR and 178 AMAX?

I'm seeing very similar issues with Varget leaning out. Can I get enough IMR4064 in here with a 178 AMAX to give me acceptable velocity?

In the past, it seemed like Varget and 2550 fps was right around the sweet spot for lower ES. However, I've never been able to break 2600 fps with Varget without much compression.