.308 Reloading Question (Size and Trim)
Replied by VTIT on topic .308 Reloading Question (Size and Trim)
That bullet has a cannelure doesn't it? That kind of limits the OAL unless you trim the cases. I can only tell you how I do it and you can see if it helps at all.
I have found book OAL is fine if you are using the same rifle that they design the round for, it's only what the book makers used to develop their listed data. I think they design so it will work okay in most firearms. But the ideal OAL is what works best in the rifle you are loading for, not what the book says.
So what I do is seat a dummy cartridge to the cannalure or seat to the book OAL whichever you are more comfortable with. Make sure it feeds smoothly ( I usually do 3-5 rounds and load a magazine with them and cycle the rifle with the charging handle). If that set up works fine and you don't see any signs of the ogive getting stuffed into the lands and grooves it will probably work and is a good place to start. You can also check the OAL before and after you cycle it and see if the bullet is pushed further into the case. If everything works and looks good you have a good place to start.
Then, once you have an OAL that will work, load some cartridges about a half grain apart and test fire them. I usually do at least 5 of each. Start low at the minimum charge, in a bolt rifle you can start a little below min with military cases, but I start at minimum for a semi-automatic. Make sure the rifle functions fine for ejecting, chambering etc. Increase charges until you reach book max. Fire them in that order until you get to the top loads OR until you see signs of excess pressure like the primer flattening out or mushrooming (extreme) around where the firing pin hits you may even see the headstamp letters getting flattened. If you see these signs before you get to the max, back off maybe 10-15% and say that's the max for your rifle. Some rifles will show high pressure signs before the max charge especially if you are using military cases.
After you find the max for your rifle you can start playing around with groups. After you find the best charge, do a whole series while varying seating depth in and out until you find the best point for accuracy. I find that my AR's don't like the bullet touching the lands and I have to seat a little shorter.
I have found that seating rifles rounds a little deeper doesn't increase the peak pressure like in a handgun load. Seating the bullet off the lands and grooves gives the bullet a little running start and doesn't raise the peak pressure as much in rifles. The best seating depth for me isn't usually a single depth but may be several thousandths wide. It also varies by the bullet shape and weight. I tried to use a seating depth tool but never had good luck with it (YMMV).
Again this is just my
just be careful and if you think it isn't safe, it probably isn't.
I have found book OAL is fine if you are using the same rifle that they design the round for, it's only what the book makers used to develop their listed data. I think they design so it will work okay in most firearms. But the ideal OAL is what works best in the rifle you are loading for, not what the book says.
So what I do is seat a dummy cartridge to the cannalure or seat to the book OAL whichever you are more comfortable with. Make sure it feeds smoothly ( I usually do 3-5 rounds and load a magazine with them and cycle the rifle with the charging handle). If that set up works fine and you don't see any signs of the ogive getting stuffed into the lands and grooves it will probably work and is a good place to start. You can also check the OAL before and after you cycle it and see if the bullet is pushed further into the case. If everything works and looks good you have a good place to start.
Then, once you have an OAL that will work, load some cartridges about a half grain apart and test fire them. I usually do at least 5 of each. Start low at the minimum charge, in a bolt rifle you can start a little below min with military cases, but I start at minimum for a semi-automatic. Make sure the rifle functions fine for ejecting, chambering etc. Increase charges until you reach book max. Fire them in that order until you get to the top loads OR until you see signs of excess pressure like the primer flattening out or mushrooming (extreme) around where the firing pin hits you may even see the headstamp letters getting flattened. If you see these signs before you get to the max, back off maybe 10-15% and say that's the max for your rifle. Some rifles will show high pressure signs before the max charge especially if you are using military cases.
After you find the max for your rifle you can start playing around with groups. After you find the best charge, do a whole series while varying seating depth in and out until you find the best point for accuracy. I find that my AR's don't like the bullet touching the lands and I have to seat a little shorter.
I have found that seating rifles rounds a little deeper doesn't increase the peak pressure like in a handgun load. Seating the bullet off the lands and grooves gives the bullet a little running start and doesn't raise the peak pressure as much in rifles. The best seating depth for me isn't usually a single depth but may be several thousandths wide. It also varies by the bullet shape and weight. I tried to use a seating depth tool but never had good luck with it (YMMV).
Again this is just my
just be careful and if you think it isn't safe, it probably isn't. Please Log in or Create an account to join the conversation.
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Replied by Sharkey on topic .308 Reloading Question (Size and Trim)
Wow. I read every single word of this post and suddenly got woozie and passed completely out...
I'm just a big dumb guy man. You gotta give a little heads up when you are gonna post this brainy stuff...
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Replied by Siscowet on topic .308 Reloading Question (Size and Trim)
excellent feed. I am going to bookmark it for when I start reloading for the 10. Please Log in or Create an account to join the conversation.
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