Posted: 1/5/2026 7:01:27 PM EDT
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Perhaps because I am cheap, I don't want to spend the $50 or so bucks for the gauge to measure the distance from the bolt face to the lands. The purpose of knowing this measurement, of course, is to load my 80 Grain Bergen VLD's for .223 so the bullet just contacts the lands when chambered. I want to work up a load for my AR for 600 yards, and I'm told the "bullet meets the lands" is the way to go. So, is there some generally accepted measurement where I can load the bullet long such that it just contacts the lands? If the answer is "no--you gotta measure your gun," I will spend the money. But if there is some generally accepted overall length for 223 with the Bergen 80 where the bullet just hits the lands when chambered, I'd like to know. Anyone? |
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Can't use a dummy round (resized/unloaded brass) with your bullet of choice to check that? Go ahead and remove the ejector, like you would for a headspace gauge check. Might try leaving the extractor in to pull the dummy round out of the chamber, but you may find out that needs removed as well (and you might have to push the dummy round out with a cleaning rod.) Seat the bullet (no crimp) and very slowly drop the bolt and see if it locks up. If not pull the dummy out and check the bullet to see if it made contact with the lands. If not, the overall length may be too short and you need to make the next dummy cartridge a little bit longer and try it again. Once you find it making contact with the lands (the bolt may, or may not lock up) you can make another dummy 0.005 to 0.010 shorter overall length and try it. I don't see a headspace gauge doing what you want anyway. It's to check the chamber, not the overall length of the cartridge. You're looking to seat the bullet out further than "normal" and your're looking at the distance from where the shoulder would make contact with the chamber to the lands. The headspace gauge isn't really checking that. It's just insuring a proper sized case will fit in the chamber when the bolt locks up. Then again, someone may disagree with me. |
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There are a few methods to do this using fired brass and one of the bullets you are working with. I have heard guys say a little blue loctite in the case neck of a fired (and not resized) piece of brass will give enough friction to chamber the round and have it seat to the lands, but I haven't tried that method myself. I will say though that with an AR you may find you are exceeding the max length for the magazine, before you get long enough to touch the lands. |
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Just get the tool man. But here: empty firearm and check again. close action and take a cleaning rod or something and put it down bore. VERY precisely measure the distance from muzzle to bolt face. now remove bolt etc. Then put barreled action vertical- so muzzle down- in a vice or something. drop a bullet you want to use down so it's sitting on the lands. take same rod and carefully work it up until you see the land seated bullet just move. VERY carefully take that measurement. The difference is the OAL of the case/bullet seated to lands from bolt face. Just get the tool man. |
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A blanket statement that a bullet kissing the lands yields best accuracy is false IMO. Your rifle might perform best as such or it might perform better at .030" off the lands. You will have to test it and see. Thus... you need the tool to do it right. As you fire the rifle and accumulate throat wear, the tool will help you determine the amount of wear and possibly an adjusted seating depth. In the long run, considering the prices of bullets, primers, and powder, is $50 REALLY an issue? |
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i've owned a few of the tools and honestly never got really repeatable results with them. take the measurement like 5 times and you'll get 5 different results. imho, one of the more consistent ways is to load a round into an empty case, with OAL where you think it will be at least 10-100 thou into the lands. color the bullet black with a dry erase marker. chamber the round and remove it, being relatively careful not to let the ejector spring drag the bullet on the lugs on the way out. then measure the scrape mark of the lands. repeat and seat the bullet 90% of the scrape mark deeper each time until you don't have a mark. ETA: you'll need a good bit of neck tension. if the bullet goes deep into the lands it may stick and you may need to pop it loose with a cleaning rod. also, be sure to measure OAL before and after to make sure the bullet didn't get pushed deeper into the case or pulled out of the case during the process. some of the sierra bullets are known to shoot well very close to the lands. however, like others said, i would test as much as 100 thou out of the lands by shooting groups. if you find out that it groups just as good 50 or 100 thou back, as it does at 10-20 thou back, then you won't have to chase the lands nearly as often. the berger hybrids and JLKs i shoot are not jump sensitive at all. I never chase the lands. |