Shooters Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
92 Posts
Discussion Starter #1
If a rifle case has been trimmed to length and the bullet seated so it isn't hitting the rifling why is it hard to turn the bolt down when it is loaded with powder and bullet. I have four rifles that are all doing the same thing. I know I have just a touch of resistence closing the bolt on a resized case which should be ok but when I finish loading the case and put it in the chamber it will seat the bullet deeper (even though it isn't near the rifling) and then on the second try the bolt closes normal
 

·
Registered
Joined
·
5,237 Posts
Cartridge OverAll Length (COAL) is a rough guideline, that doesn't necessarily apply to all bullets, or all chambers. I have a .243 that requires 100gr Sierra Semi Spitzers to be about 1/4" shorter than a similar weight Hornady or Speer.

In any case, if the empty case seats without effort, but the case with the seated bullet does not, you are a bit too long. With a hot load, you might have a problem.
 

·
Super Moderator
Joined
·
13,430 Posts
George, sounds pretty much like the bullet must be near the rifling. How are you making that determination? Remember, the rifling is less than a hundredth of an inch narrower than the bullet, so it touches the bullet just above the shoulder where its ogive meets its bearing surface. This means some bullet shapes with short ogives have to have shorter COL to avoid touching the rifling than longer ones do. The only purpose of the SAMMI COL number is to ensure the finishished cartridge will fit in a SAAMI compliant magazine. What your chamber needs can be entirely unrelated.

Please let us know what bullets you are using and perhaps we can suggest a COL for them? The bullet manufacturer's manuals usually give the COL they used in testing the bullet. One of us can look that up for you. Alternately, you can buy an overall length gauge, such as the Hornady one for your calipers or a separate one for each chambering you have, like the RCBS Precision Mic.

You can also resize a case you don't mind sacrificing and cut a split in the neck with a Dremel tool or careful use of a hack saw. This will hold a bullet, but not too firmly. Start a bullet into this case just far enough that it doesn't fall out, then chamber it with your thumb, pushing it all the way into the chamber until it stops firmly. The throat will have finished seating the bullet. Now take a cleaning rod and gently push the bullet nose just enough so the cartridge is free to remove. That makes sure the throat doesn't grab the bullet enough to pull it slightly back out. Carefully remove and measure the length of the cartridge from base to tip (the COL). This is the maximum COL you can have before pushing the bullet into the throat (the touching of which raises pressure around 10,000 psi, by the way). You want yours shorter than that for general purposes.
 

Attachments

·
The Troll Whisperer (Moderator)
Joined
·
24,112 Posts
Also, if you're loading compressed powder cartridges, the bullet will rebound without a crimp and grow to a longer length until the compression is relieved, if the neck tension isn't too great.

The answer of bullet configuration is also to be considered.
 

·
Registered
Joined
·
43 Posts
you have already answered your question with your post.and the other replies have given you good info.

you are still seatting the bullet with the bolt.thats why its easier to close the bolt the second time you chamber it.try marking all over the bullet with a sharpe so that it will show you the markings from the lands.this will even help you out finding the lands with differnt bullets.it works every time I use this way of finding the lands.and I still haven't bought a gauge yet.

hope we are able to have helped ya.
 

·
Registered
Joined
·
863 Posts
"you are still seatting the bullet with the bolt.thats why its easier to close the bolt the second time you chamber it."

Yep. You are seating more than close to the rifling, you are seating hard into the rifling.
 

·
Registered
Joined
·
92 Posts
Discussion Starter #7
What I found is I wasn't setting the shoulder back enough and when I chambered the round it was setting it back changing the COAL.
 

·
Registered
Joined
·
13,291 Posts
George,

You mentioned in your OP, that your bolt closed hard the first time, easy the second time, and that you were concerned about how much your bullet was being pushed back, reducing your COAL. Now it's looking like the shoulder of the case was not being resized enough, and that was causing the issue. This begs a few questions:

1. Were these cases not originally fired from your gun?

2. Were you just neck-sizing the cases, before reloading?

3. Exactly how much was your COAL being reduces? (I'm trying to imagine it being more than ~ .005", if you were just using the camming action of your bolt. to achieve it...)
 

·
Registered
Joined
·
92 Posts
Discussion Starter #9
broom_jm,

I neck sized brand new brass and then after it was fired once I was setting up my die for a crush fit to the chamber. If you don't size quite far enough I have found it can or will push your shoulder ahead. The COAL was being changed from 2.810 down to 2.802 or 2.803. By setting the sizing die down another 1/32 to 1/8" more it solved the problem. BTW I fired the 20 rounds I had loaded and I got a 1/2" average with them for six three shot groups.
 

·
Registered
Joined
·
13,291 Posts
Well, it definitely sounds like you have the problem solved, if you're getting groups like that. :)

I can't say I've ever noticed the shoulder moving forward on my cases, when resizing. Maybe they do move a bit, but not enough for me to realize, when closing the action and it hasn't shown up in my groups.
 

·
Registered
Joined
·
614 Posts
To get a perfect fireformed case you should full length resize before the first firing or first reloading . Neck sizing brass that hasn't been fired in your chamber makes no sense . Full length resize , trim , ( .010 " under trim to length won't hurt anything ) then when you neck size you will actually be accomplishing something . If you were shooting half MOA before neck sizing , I'd like to know the caliber and if it's for sale !
 

·
Super Moderator
Joined
·
13,430 Posts
George,

Am I correct in guessing that you are neck sizing by short stroking a full length seating die rather than using a neck sizing die? That would explain what you see, as a standard sizing die not only pushes the shoulder back but also narrows the fired case. Narrowing the case squeezes it out longer, moving the shoulder forward until the shoulder portion of the die sets it back again. I have a diagram exaggerating that. If I can find it, all add it on here.

Meanwhile, I'd strongly suggest you look at the Lee Collet Die. It is inexpensive, takes a little getting used to, but at least one British shooting publication and a number of us independently have had the result that it is the neck die that is least likely to pull the neck off-axis with the rest of the case. You'll still need your FL die from time to time when the brass packs up too tight, to restart the process, but the Lee die is a better neck sizing mousetrap. I have not had a chance to try one of the newer Redding sliding sleeve bushing type neck sizers, but they may also keep the neck straight. The Lee costs a lot less.
 

Attachments

·
Registered
Joined
·
13,291 Posts
Nick,

As always, excellent explanation and diagrams! You should do this professionally, or something. ;)
 

·
Registered
Joined
·
92 Posts
Discussion Starter #14
Nick,

The only time I neck size is with brand new factory unfired brass the rest of the time I PFL size. I use Bonanza bench rest dies for the calibers I load for. The caliber in question is a 6mm Rem. It is a CDL that Remington didn't produce. I had a brand new CDL stock that Remington gave to me and I bought a 7-08 BDL that was manufactured in 1988 from a friend in Maryland. I had the action rebarelled with a Douglas barrel in 6mm Rem and then had it glassbedded and floated using my CDL stock.
 

·
Registered
Joined
·
13,291 Posts
I think the general consensus is to always FL size new, unfired brass. That way if you have a tight chamber, you know your cases are going to fit and will "fire-form" on that first shot. What I find odd is that you neck size new cases, which you should always FL size, and then you don't neck size after the subsequent firings, which is when most people who bother with neck-sizing feel that it is beneficial. Kinda doing it backward, really.
 

·
Registered
Joined
·
70 Posts
I'm curios about this two i'm new to this and been reading a lot about it and that definitely seems backwards to me.

Are you using a fl die custom made to chamber?

Even if so why neck size the unfired brass?
 

·
The Hog Whisperer (Administrator)
Joined
·
36,654 Posts
Neck size the unfired brass to even out the little dents and dings that seem to happen in shipping, especially with bulk brass. New brass is pretty darn soft.

I set up all of my FL dies to push the case shoulder back about 0.002" or so as compared to when they are fired. Partial full-length resizing has never worked for me, and neck-sizing lets case necks lose concentricity with the case body. The Lee neck sizing system is the exception to that but I don't mess with it much.
 

·
Registered
Joined
·
614 Posts
You have me confused Jim ! If you don't neck size after firing , what holds the bullet in place . I you don't resize the neck you have no neck tension !
 

·
Registered
Joined
·
92 Posts
Discussion Starter #19
Mike G,

That is what I meant by PFL, I try to fit the case to the chamber. I have a Hornady Headspace kit on the way now and 0.002 shoulder set back is how I am going to size my cases. I have never had much luck with neck sizing, I always seemed to get better accuracy with PFLing.
 

·
Super Moderator
Joined
·
13,430 Posts
Well, I am being slow to catch on. You must be referring to neck sizing by running a case part way into a full-length die? That partially sizes the neck, leaving a short portion at fired length diameter to help center the bullet. It seems to work for some people, but depends on your chamber dimensions.

First, you want to use the Sharpie or Magic Marker trick, but use it on the case body. See how far you can run the case into the die before the sides of the case body start to make contact with the die? If you go any further, you will be squeezing the shoulder forward as in my middle illustration in my last post. That can happen too early if your chamber's diameters are on the generous side. Brass can spring back from a little contact, but not much. When you have your gauge, you will be able to find how far you can run the case into the die before that results in lengthening, exactly?

If you have to go deeper to get the neck sized still further back, then this whole approach isn't going to work out for your chamber and cartridge, and it will be time to get the Lee die or some other special neck die.

Also check the diameter of the unresized portion of the neck above the shoulder. Check it after firing and again after the partial insertion into the FL sizing die. If it is being fattened up by the partial neck sizing, then it may no longer chamber? Whether or not this happens depends on the hardness of your brass and how much force the die is applying to achieve partial resizing of the neck? If the brass is thick, that may be too much for the neck below where sizing stops? Again, the special neck die becomes the solution.

We need a new term for this kind of sizing technique. Partial and Full in the same term seems like an oxymoron in the making.
 
1 - 20 of 21 Posts
Top