Just starting to reload, is it generally considered safe to load rounds "jammed" into the lands? I'm starting at the lowest suggested load and working my way up in .5 grain increments. Is this a good plan? How do I know if a manufacturer's maximum published load will fire safely jammed? Any advice would be appreciated.
- Thread starter HT0317
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- 300 win mag jammed
Short answer....You don't "know if a manufactures's maximum published load will fire safely jammed."
It is, however, generally considered safe to load rounds with a 0.01" - 0.02" jump to the lands as opposed to jamming.
If you are just starting to load, I think you should stick to the load data in the books until you get some experience under your belt....It's safer that way.
Load to SAMMI specs; from there you can gradually increase your COL by 0.01" to see if your groups improve while checking for pressure signs.
There is no magic number for COL that works in every gun, you have to experiment....I, personally, do not recommend jamming the bullets into the lands - but, many do have good luck with it. To each is his own...
To answer your first question..... I don't think it's generally considered safe to jam the rounds into the lands....others may say differently though.
With jamming there is opportunity for over pressure if you are not careful. I have seen catastrophic failures in my time because of a "perfect storm" of reloading errors; jamming rounds have been a factor in many of them.
With jamming there is opportunity for over pressure if you are not careful. I have seen catastrophic failures in my time because of a "perfect storm" of reloading errors; jamming rounds have been a factor in many of them.
Jammed is worth about 0.5 gr of powder, generally speaking.
Why jam? Jump'em 0.040 to 0.080" (depending on where the shoot best from your rifle) and save yourself the hassle of constantly chasing the lands.
Need to know chamber dimensions to be able to tell you much of anything or an OAL for when bullet touches lands. Brass, primer, powder and bullet to be used would also be useful information.
I always start off the lands. Some rifles in what is considered BR calibers do benefit from jamming but many do not. I jam bullets in my 6mmBR tubegun. You will be surprised how well many bullets can shoot when they are jumping. Some can be jumped a very long distance.
When you are getting near the top end of a load even for a 300WM .5gr might be too much too fast. I have a 308 where .2 or .3 gr of powder is the difference between a very rounded primer and a blown primer.
When you are getting near the top end of a load even for a 300WM .5gr might be too much too fast. I have a 308 where .2 or .3 gr of powder is the difference between a very rounded primer and a blown primer.
