Home Forums Reloading Big Game Rifles Just Wondering..

And yet another greenhorn question..

I always try for an OAL that puts me 0.050 off the lands, but what happens if you seat a bullet so that it makes contacts with the lands?

The rifle quite often shoots smaller groups... or sometimes not. If you're at the bleeding edge of pressure dont do it. With lesser loads light contact or a thou or 2 off of touch wont boost pressure enough to notice. A hard jam into the rifling might cause problems. Be aware & careful if you try this. I usually back down a grain or so, test fire & work back up if possible.

Seating depth is one of the variables for tuning a load to your rifle. The all copper stuff seems to like a bit of a run at the rifling, but cup & cores often like to be closer to touch. With C&C, I usually start development at touch if possible. That way there's only one direction to go once the approx. powder charge is found. Magazine length can throw a wrench in the above if your rifle has a longer throat, but a little experimenting can still tighten groups.

Measuring to the bullet's tip doesn't work all that well. Some sort of dial caliper attached ogive measuring tool is a good starting place. Welcome to the rabbit hole.

It doesn't have to be a "rabbit hole" at all. OP, just load your cup and cores to .020" off the lands and your mono metals to .025-.100" and you will be fine. For a hunting rifle and even most precision rifles, you won't need to kiss the lands. If you want reliable and precise hunting loads, .020" off the lands work just fine. You also don't need comparators. Just a good grasp on averages and common sense.. I often urge guys here saying they "need" certain tools to prove what they are preaching, but they never do. What they do is often confuse new handloaders, making them think they need all these unnecessary tools and gadgets. A lot of guys searching for better when they often have no clue to use what is right in front of them. Keep it simple applies here..

Maybe not, but they do help especially if the bullet manufacturer moves the ogive 5 or so thou. That being a major complaint as to fugging up a good load. Without the comparator to measure bullet base to ogive you be pizzing in the wind. Also have seen as much as 5 thou diffrence in seating depth due to measuring OAL from tip to base due to tip length. Another factor is no 2 chambers are exact even if from same manufacturer. No tool is worthless if it can increase your consistency.

What 358 said.
If you are near max velocity, or in absence of a chrono near/at max powder charge, it may be a good idea to back off the powder charge a wee bit as you move the bullet closer to the lands. Generally moving closer to the lands increases velocity which in turn means the pressure is increasing.

For a hunting rifle and load and I won't be touching the lands, and usually try .015 off the lands to start with for most conventional C&C bullets. Copper bullets and sometimes VLD's tend to like being further away from the lands.

As Swifty said, a comparator is a quite handy tool to have and not very expensive.

An interesting side point. When I was fire forming .257 Roberts Ackley cases I seated some old 100gn Norma bullets well into the lands with a light charge of H4895. I fired 25 rounds into a group about four inches at 50 metres.

But I never seat hunting rounds to touch the lands. I go 20 thou off for my .222 and .30 thou for bigger cals if I can as sometimes the magazine box won't allow bullets to be seated near the lands. I wouldn't recommend seating bullets into the lands for hunting rounds.

BSA, like Swifty said, what do you do when you get a new lot of bullets & they're different? Dick around for half an hour or whip out a comparator? Time saving tools are a rabbit hole all their own with side tunnels that cross over to accuracy.

The bullet comparator is not a new concept. When I ran a small accuracy minded shop in the 80s & 90s, there was the Sinclair big nut @ $12 or so, which I personally think is a screaming pain in the ass to use or the long defunct Davidson individual caliber bullet comparators from 17 thru 458 for around $9 each. I sold the schidt out of the Davidsons & still have a set for my use. This was before the Stoney Point sets, which is now sold by Hornady for about $35 each, came out. Hardly expensive for as useful as they are. The comparator sure does streamline the process once the distance has been found. So you know, comparators do not measure any set dimension. They only compare. The Sinclair will not give the same readings as the Stoney Point or the Davidson. In fact, even 2 different Davidson tools may read differently, so the same tool should be used for all comparisons.

https://www.brownells.com/reloading...-style-bullet-comparators-prod83792.aspx

I have an old Sinclair nut that will do 22,24,25,27,28,&30 cal. sitting in the drawer that the OP can have if he PMs his address. In my opinion it's a starter tool, the Stoney Point/Hornady is absolutely a step up in ease of use. Benchrite is selling copies of the Davidson tools for $34.50 in only 5 sizes. These are not cheap but probably another step up, but limited sizes.

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Way back in the dark ages, to find the touch length, I used to drop the bullet being checked into the chamber (hoping it would stay point on) & hold it there with a pistol cleaning rod while sliding another cleaning rod in from the muzzle & marking the rod. Having long arms helped a lot. The long rod had already been marked for length to the closed bolt face. An approximate OAL to touch would be the difference between the 2 marks which still needed to be checked as the rod marking was most times less than right on. This was done with each & every bullet type tried. I also tried slitting a case neck then closing the bolt to seat the bullet which plain doesn't work very well.

The Stoney Point OAL set makes it much easier to find the start point. A curved tool is also made for actions with no rear access. Threaded cases are available for $5-6, or you can thread your own with an appropriate drill & 5/16-36 tap. Expensive? Not really. It's a tool that with care will last a few lifetimes. Useless? Not if your time is worth anything or your arms are short.

https://www.midsouthshooterssupply.com/item/00005c1000/lock-n-load-c-1000-straight-oal-gauge

Here's the bullet comparator starter set. Single caliber comparators are also available if you only want one or two.

https://www.midsouthshooterssupply....comparator-basic-set-body-with-7-inserts

The complete set costs a bit more.

https://www.midsouthshooterssupply.com/item/00005b14/lock-n-load-bullet-comparator-set-(body-with-14-inserts)

358,
I bought the SP comparator shortly after they came out (30+ years ago?) and have been using it ever since. I now have two calipers dedicated to comparator bodies and one caliper dedicated to the headspace gauge body. I consider the those two tools among the more important tools on my bench. A while back I also bought the OAL gauge, the (intentional on Stony Point's part) super secret oddball tap and make my own cases to find the lands.

Yeah. the tap size was a head scratcher. Got a couple of them on fleabay for like a buck fitty. Chinee stuff, but they work fine on brass. None available in local hardware stores. The old guy at Western Auto just laughed. Wish I still had a drill press. When hand drilling, the holes dont always come out straight. Wilson case trimmer holders in a lathe is the schidt, but the only access to a shop I still have is an hour's drive away.

15-20 bucks for the bit and tap, 10 bucks for the tap on Amazon.

So what size drill bit and tap are used to make your own modified cases?

5/16x36 tap. 7.3mm or 19/64 bit. The 19/64 bit will give shallower threads.

IMO, a comparator is pretty much indispensable. I was once hard-headed enough to think it was unnecessary, but I learned otherwise after some struggling. I still don't believe anything works better than a split-necked for finding the zero-to-lands seating depth, though. It just takes a few repetitions to get a good number, and it's all just a reference point anyway unless your trying to establish the kiss length which I never use for seating anyway.

I made cases with a 1/4 20 tap and used threaded rod from the hardware store and straws.I'm only using them on bolt actions though.It works for finding max OAL.