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7mm-08 loading...lengthy question. UPDATE 4/10/10
Mark Leonard
Member Posts: 31 ✭✭
Guys, I recently purchased a custom made 7mm-08 at an estate auction. It was made from a Mauser action, douglas barrel, and I believe a timney trigger. Not sure on the trigger but it breaks cleanly at 2 lbs every time. This will be my first experience ever with a Mauser built gun, and I am looking for some loading info. I was told by some friends that these rifles tend to like a longer COAL than standard, and have a overall length gage and case from Midway on the way. The two bullets that I will be primarily loading will be Hornady 139 grain SST, and Sierra 140 grain SBT. Powders I currently have at home for this are IMR 4064, IMR 4350, and H335. I am not against trying different ones either, so don't be shy if you have a favorite load with a different powder. I would appreciate all information about loads, 7mm-08 caliber feedback, etc. Thanks in advance, Mark
Comments
I have never used the lighter bullets to load 7MM-08 because I had 150gr Nosler BT's on hand. I load those with H414 and consistently get sub-moa groups at 100yds. Nosler #5 shows 42.0gr starting load and 46.0gr Max. I load 44.0gr with Fed 210's and get just over 2600fps in a 26in barrel. As with any load data be sure to work up loads. Hope this helps.
On a custom gun from an AUCTION (or really any gun other than new) I would consider taking it by a gunsmith and request that the Head space be checked (using a Go NO Go gauge) and let them do a once over of the gun! Reason I say this about the head space is some of the Mauser actions had weak and inferior metal in the receivers and head space would get out past maximum, due to wear behind the bolt lugs in the receiver)
Guys, I recently purchased a custom made 7mm-08 at an estate auction. It was made from a Mauser action, douglas barrel, and I believe a timney trigger. Not sure on the trigger but it breaks cleanly at 2 lbs every time. This will be my first experience ever with a Mauser built gun, and I am looking for some loading info. I was told by some friends that these rifles tend to like a longer COAL than standard, and have a overall length gage and case from Midway on the way. The two bullets that I will be primarily loading will be Hornady 139 grain SST, and Sierra 140 grain SBT. Powders I currently have at home for this are IMR 4064, IMR 4350, and H335. I am not against trying different ones either, so don't be shy if you have a favorite load with a different powder. I would appreciate all information about loads, 7mm-08 caliber feedback, etc. Thanks in advance, Mark
Mark Leonard,
congratulations on the new purchase! I think you've done very well! {note two exclamations...that means I really like your decision}
Since you've already decided on the bullet weights of around 140 gr. twist won't be an issue. Any 1-12" twist will stabilize bullets of that weight (length actually) and lighter. It will even stabilize the Berger 140 gr. VLD's.
Now, if you want to go heavier the first thing I would do is check the twist. You do that by taking a firm fitting patch on a jag with a cleaning rod that rotates in it's handle freely. I recommend Dewey. Anyhow, insert the patched jag in the bore (from chamber end) where it's firm and mark both top center of the rod and how far out the rod is. Note: you need to mark top center back at the handle. As you push the jag through the barrel note that it's rotating consistently. When it rotates back to it's original position, stop. Measure the distance now that's sticking out of the barrel. Subtract that from what was sticking out. That is one rotation in "x" inches.
A 1-10" will stabilize up to a 168 gr. VLD/ULD type bullet. It won't stabilize a 180 VLD. That takes a 1-9" For that matter it won't stabilize a 175 gr. non VLD bullet very well either. It does very very well with 168 spitzers like the 168 SMK.
A 1-8.5" is best as it will stabilize all the heavy, high BC bullets. It will also work fine for anything on down to 100 gr.
My suggestion is find out what you've got. Work with all the bullets you can. Even if you have a 1-10" 140 gr. bullets work just fine.
Also, on the powders for that caliber, 4350 of any flavor is about the best. 4064 will work for lighter bullets up to the 140. H335 I think is a little fast for all but the 100 gr.
You did it right. I know a little over 1/10" of an inch sounds like a lot but that is the difference between a Secant (Hornady) and a Tangent (Sierra) ogive.
Have fun, I had one rifle that didn't like Hrdy either, their profile is different than some others. Sandwarrior said the technical names of ogive. Other rifles did very well with them. I guess that's why their is no "magic" load.