Bullet seating depth - Updated!

M

mac805

Member
I am new to reloading, and last night I loaded a few sierra 85 gr HPBT in .243 win. I seated the bullets according to the COAL listed in the sierra manual (2.65").When trying to chamber the rounds, it took some force to close the bolt, and could see marks on the bullet where it touched the lands. I know I need to seat the bullet deeper, but how far off the rifling should I start? I am loading at the starting load of H4350 and working up. Any advice is much appreciated.

Thanks
 
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The easiest way is to buy a Honady OAL Gauge. Another way is to use a Fired case and barley mash the neck then mark a Bullet with a magic marker barely insert bullet in case and stick in Rifle and close the Bolt. The case should leave marks on the bullet and then you can figure out from there what you need to do. I would also advise getting a wood dowel to shove down the end of the barrel if you are anal about your Crown. More than likely the bullet will get stuck in the lands. Also before you get to carried away does the cartridge fit in your magazine at the lenght you are trying. If they don't you need to shorten them up or you will have just a Single shot rifle.
 
Hey Mac, sometimes your bullet seater will leave marks on your bullet too. Are you 100% sure they're coming from the lands of your rifling?

You didn't mention anthing about the history of the rifle itself. If it's a factory rifle with a factory barrel, it would be "odd", but not impossible, for a published C.O.A.L to be too long.

Could it be your brass not sized properly? Give us some more information. Once fired brass? New brass? Will a freshly resized case chamber fine?
 
Originally Posted By: duckdog
Could it be your brass not sized properly? Give us some more information. Once fired brass? New brass? Will a freshly resized case chamber fine?

This has been my experience. The cases have not been full length sized. Maybe you're not running the case through the die fully?
 
Grizz here.
I'll take a sized case, NO PRIMER AND OR POWDER! and cut a slot down the case neck in two places 180 degrees apart then deburr it. Then I'll take the firing pin out of the bolt. put the bolt back into the reciever. Set your bullet seating die to barley seat one of the bullets you want to use just deep enough to keep the bullet from falling out of the case. Incert this inert round into the chamber by hand then close tha bolt slowley. As the bolt closes the rifling will push the bullet deeper into the case. The slots you cut into the case neck allows the bullet to slide in the case neck. Open the bolt slowley, remove the round and measure the overall length with dial calipers. Write down the measurment. Repeat this a few times and you will know what your cartridge length is with the bullet seated at the lands. Then you can seat the bullets at the lands or .010, off the lands, or deeper. This you will have to experiment with for accuracy. Grizz
 
If you loaded to the manuals OAL, then Duckdog and Heretic could very well be right on target.

Back to your question----There are various tools to help you measure the dimensions of your rifles chamber. Hornaday, Stoney Point, and I hear RagnCajn, here at PM, has a good tool too. (Sorry I haven't tried it) Usually it's recommended not to seat into the lands, but to keep the bullet back. I'm sure someone will have the accepted distance, I just can't remember right now.

However, most non-custom rifles have lots of Freebore and this often makes it hard to seat a lot of bullets up to the lands.

Always make sure that the loaded cartridge will fit in your magazine.

Often it's recommended that the bullet should seated at least one bullet diameter into the case, but that's flexible depending on cartridge, caliber and gun.
 
can you see the marks left by the rifleing or is it just a scratch from the feed ramps? does a loaded round eject easily?

The cheapest way to find COL

take your ramrod and run a screw into it with the head cut off, close the bolt making sure its cocked, run the ramrod down the barrel until it hits the bolt face, put a pencil mark on it, then take a bullet your gonna use and slide it in the chamber, use a pencil (erasor end first) to push it into the lands (gently) then slide the rod back in till you feel it just touch the bullet, put another pencil mark on the rod right at the end of the muzzle. measure between the marks, thats it, or you can buy one of randy's handy dandy col tools (from Rag'n Cag'n a mod on this forum) which work very well also.
RR
 
Duckdog and Heretic have a good starting point for you, if you are new to reloading I would suggest starting by making sure that your dies are adjusted correctly, after sizing measure the case, to long? then trim. Try chambering just the empty case. Do you have your dies set to crimp? Look at the case in the shoulder area, if you didn't chamfer the case mouth you could have wrinkled it. Even the slightest little bulge will bind on the chamber walls. If none of this works you can P.M. me, I'll give you my phone # and I'll try to walk you through it.
 
To check my brass here is an easy test, before you load the rounds for hunting, chamber every round as a Quality Control check.

To check for over all length of your chamber of the gun, Smoke the end of the case with a cigarette lighter and carefully chamber and extract it. Look at the end of the case, if it needs trimming, you will see where the smoke was rubbed off the end of the case where it butted up against the end of the chamber.

There are various gages that will help you establish your actual OAL till you thouch the lands, invest in something.

Bottom line: if you seated the bullets to the OAL listed in the sierra manual, you do not have the bullets seated too far out, you have a problem with full length sizing or the cases are too long and need trimming.

Good luck!
 
Originally Posted By: TrapShooter12The easiest way is to buy a Honady OAL Gauge. Another way is to use a Fired case and barley mash the neck then mark a Bullet with a magic marker barely insert bullet in case and stick in Rifle and close the Bolt. The case should leave marks on the bullet and then you can figure out from there what you need to do. I would also advise getting a wood dowel to shove down the end of the barrel if you are anal about your Crown. More than likely the bullet will get stuck in the lands. Also before you get to carried away does the cartridge fit in your magazine at the lenght you are trying. If they don't you need to shorten them up or you will have just a Single shot rifle.


Get the Hornady OAL set up, you wont be sorry and it is a tad more accurate IMHO than the other ways that have been suggested, BUT the other ways will work also but not as easy to get just right. I have the set ups for 5 different cartridges. And love it.

DAB
 
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Thanks for the input guys. I am on the road, and will investigate a little further tomorrow. The brass is once fired winchester, and the gun is an almost new (about 60 rounds fired)Ruger M77 Hawkeye. The reloaded ammo does fit in the mag without any length issues, and the marks left on the bullet are spaced at regular intervals (appears to me to match the rifling) and look very different from the light ring on the bullet from the seating die. I did check the brass length after sizing but did not attempt to chamber one of the resized brass. I will double check this as well when I can take a closer look tomorrow.
 
I had some time to sit down and investigate my issue tonight, and here is what I found (sorry if it gets a little long)

The first thing I tried was chambering my resized brass, and I was able to close the bolt easily with no resistance.

I inspected the loaded (2.650" COAL)cartridges that I had tried to chamber, and there were definite marks spaced at regular intervals at the point along the length of the bullet just as it reaches full diameter back from the tip. They sure look like rifling marks to me

Next, I tried my dad's .243, and the rounds chambered perfectly without any pressure on the bolt. No marks were left on the bullet by his gun.

I then tried the method of using a dummy case and seated the bullet deeper until bolt closed easily. This was just over 2.630" COAL with the Sierra bullets.

I seated the bullet on a live round to 2.620" COAL and this round chambered easily without pressure on the bolt and no marks were left on the bullet.

I also check a few different factory rounds I have that chamber fine, and they were both about 2.640" but the bullets tapered more to a point than the sierras (I don't know how else to say that except the nose of the sierra is a little shorter and fatter that the others).

Based on this information, does it sound right that my gun's chamber is too short for the 2.65" COAL?

If doesn't seem correct, any other ideas?

Thanks for reading and all your feedback.

Mac
 
It sounds like the difference in the ogive on the various bullets may be where the problem lies... Your rifle may be blessed (?) with a 'short chamber and need to be loaded accordingly...

You should probably get your hands on a chamber measurement tool and a bullet comparator (Hornady makes both), and get your exact measurements... They are both easy to use and will allow you to tailor your loads to very exacting specifications, and probably excellent accuracy.
 
I have just the opposite problem in my Rem 308. The throat is so long that the Shells will not fit in the Magazine when I set the Bullets to the Lands.

That was why I had asked if your Shells fit in th Magazine in my first post.
 
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I have plenty of room in the magazine, even at the Sierra tested length.

I feel better about it since my brass cycles just fine in the gun, and the completed rounds had no problems in the other gun I tried.

It just made me a little nervous when I had problems with the specified length in the Sierra manual.

Thanks for all the input.
 
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