01-31-2022, 12:59 AM
daved20319 Wrote:So I recently got back into the Grendel world, put together an AR using a BCA side charger upper and Aero lower. Not looking for a long range precision load, my max range available is maybe 400 yards, so I planned on staying with the lighter bullets, mostly the 120-123 class. However, I did have some partial boxes of 130 gr. ELD-M's and TMK's, so decided to load up some test batches. As load data for the two bullets was pretty nearly identical across several data sources, I decided to use the same charge weights of Varget with both bullets, only altering the COL per published data. No problems with the ELD-M's, but the TMK's were a different story. The first couple of charge increments were fine (.3 gr. increments), but then I started seeing some bullet deformation from the seating stem, as well as growing COL. This continued to get worse as the charge weight went up, until it got to the point that I couldn't seat them deep enough no matter what I did. Seating die is a Forster micrometer. Not happy, but slept on it, and decided to pull them down and try again with new bullets. Same result, and now I have a bunch of bullets that aren't good for anything but sighters/foulers. Pulled them all down again and reloaded with a different powder to use as sighters/foulers, the bullets are damaged enough by the seater that I have no faith they'll group worth a damn.
So where did I go wrong? I realize this is a rather long bullet, and that Varget is a bulky powder, but none of the load manuals I checked showed even max loads of Varget as compressed, and certainly not compressed enough to squish bullets. Even reloading them using Ramshot TAC, I was getting some crunching, and that was with a middle of the charge range load. Is the Forster seating stem a bad fit to this particular bullet, or is it just a bad bullet choice for this particular cartridge? I know I loaded a few of these with my previous Grendel, a Howa 1500 Mini. No problems, but that was with a different seater, and a different powder, so not an apples to apples comparison. Regardless, I definitely won't be using these again in the Grr, mostly just curious what others have experienced with this bullet. Thanks.
Dave
Diffrent cases have diffrent case capacity and your loads were grossly over compressed and now you have done irreversible damage to your seater stem.
The seater stem in the foster micro seater is very very soft. It says it in the instructions to not use it for loads anytime their is powder compression. I learned from first hand experience.
You need a diffrent powder if you have h4895 that would help but it to is a bit bulky for loads that short. Varget will work and produce great velocity's if you can load them out very long like in the 2.390 to 2.4 load length range anything at 2.300 are shorter is going to compress with heavy bullets and varget in the grendel case.
Edit to add.
You could try a 9 or 12 inch drop tube. But I dont think that's going to be enough help. Your better off trying a diffrent powder.