How do you determine OAL and seating depth?

[Boomer]

Reluctant yes,but most will do what it takes to win,and crimping has certainly not caught on with target shooters.



I for one have never had to seat into the lands,or crimp,yet I am often able to obtain sub moa ,and usually much better with all of my current rifles.In fact not all of my rifles shoot best when seated even close to the lands.In fact I seat the barnes tsx and mrx .050" to .070" off the lands because that is where they shoot best in my rifles.I am able to consistently obtain 5/8 moa groups with three different rifles at these seating depths.I have hunted with two 300ultramags,two 7mmstws,one 375 h&h,one 300wby,one 8mmremmag,one 338x8mmremmag,most of which provide more recoil than the average hunting cartridge in use today,as well as other smaller capacity magnums,and I have never had an issue with bullets being pushed back into the case.
I would crimp for use in tubular magazines,or larger bore handguns or rifles,but it just isn't necessary for the vast majority of cartridges/rifles now being used by hunters.And I am certainly not severely limiting my choice of bullets or seating depths to use only bullets with a cannelure.

Bullet set back is a function of bullet weight and recoil. This can be born out by anyone who has used a kinetic bullet puller in that heavy for caliber bullets pull easier than light bullets. That does not mean that light for caliber bullets are immune from set back, quite the contrary, and this is significant with the interest in light bullets due to the idea that high velocity solves all ills. A light bullet is shorter and often is fueled with a faster burning powder resulting in more air space inside the case body. This gives the bullet room to set back and the shorter OAL of the lighter bullet means there is more room in the magazine for it to be slammed around during recoil. The lighter bullet may take more firing cycles to set back than the heavier bullet. Most hunter will probably not encounter this, but those of us who keep our rifles loaded for weeks or months on end, and who have a tendency to keep adding rounds to top off the magazine off without changing out the bottom rounds will run into this sooner or later if they don't crimp.

The accuracy you report is impressive, but how is it an advantage in the field over a 1 MOA rifle ammo combination. I do a fair bit of shooting, and now and then I can pull off a 1 MOA shot in the field. Not a 1 MOA group, but a single shot that lands within a half inch of my point of aim. I also have a target I fired with my .308 target gun with a group that measures .107". Neither of these things can I do on demand, particularly considering the kind of winds we often experience here. In the case of the target group, I doubt if I could do that again on a fluke, so these things exist solely as curiosities.

What we need to be concerned with is what we can do on demand, and what we can do to support that. I can shoot 2 MOA in the field on demand within certain parameters. I must have an unencumbered view of the target within 300 yards, and I must have time to shoot from a supported position. Shooting prone I can cut that to 1.5 MOA, but shooting off hand I can match the 2 MOA only in calm conditions and on a day that I am on my game. This is nothing special, and there are lots of folks who can better that, but I believe it is better than average, and is still along way from .5 or .75 MOA.

Being restricted to bullets with cannelures is no hardship. You seem to prefer TSX's and banded bullets provide a nice crimping groove, in fact more than one.

 

[Boomer]

Below are two 7mmstw cases with 162gr hornady bullets seated so that the amount of jacket extending from the neck to the base of the lead tip is identical.I held one cartridge in my hand and struck the bullet with a steel hammer until the lead was flattened as you can see.I remeasured the amount of bullet jacket from the case to the base of the lead tip,and it has not changed.

If the base of the bullet is tight against the powder column, chances are it won't set back. But when the bullet is set out to meet the rifling, particularly a short bullet, the bearing surface is shorter, there is airspace in the case body, and room in the magazine for the round to get beat around. It all depends how many firing cycles happen above it. I had a .375 Ultra case loaded with a 380 gr bullet that was crimped in, and the set back couldn't push the bullet in, but it began to change the shape of the cartridge case, actually expanding the shoulder. I fired it while it would still chamber. I expect that round had 50 rounds fired over it, as in good weather that is my cleaning cycle.

 

[stubblejumper]

Bullet set back is a function of bullet weight and recoil. This can be born out by anyone who has used a kinetic bullet puller in that heavy for caliber bullets pull easier than light bullets. That does not mean that light for caliber bullets are immune from set back, quite the contrary, and this is significant with the interest in light bullets due to the idea that high velocity solves all ills. A light bullet is shorter and often is fueled with a faster burning powder resulting in more air space inside the case body. This gives the bullet room to set back and the shorter OAL of the lighter bullet means there is more room in the magazine for it to be slammed around during recoil. The lighter bullet may take more firing cycles to set back than the heavier bullet.

So do you really believe that the recoil of the average hunting rifle is more likely to set back a bullet more than striking that bullet with a steel hammer as I did for the pictures that I posted?I don't

And by the way,the bullets in my pictures are 162gr,hardly light for caliber.

If the base of the bullet is tight against the powder column, chances are it won't set back.

The pictures that I posted are of empty cases with bullets seated.

Being restricted to bullets with cannelures is no hardship. You seem to prefer TSX's and banded bullets provide a nice crimping groove, in fact more than one.

From the FAQ ssection on the Barnes site.

Do you recommend crimping your bullets?
We usually don’t recommend crimping our smaller-caliber bullets

Since Barnes obviously has much more experience with their bullets than you do,I will observe their recommendations.They only recommend crimping their .375" and up bullets,and those used in tubular magazines or handguns.

 

[Hotwheels81]

and i dont pound on my bolt's either... a firm push with my palm is all it has ever taken on 4 enfield's, 2 remington 700's, 1 tik-tac, 2 ruger's, 1 mosin etc etc... LEE and RCBS die's...

congrat's... your way work's for you with your brass, your dies, your bullet's, your enviroment, your rifle's and there's possibly alot of other people out there who get away with doing it that way... i however have not been that lucky...

this thread went to $h!t 2 pages ago... i think the original question was answerd...

 

[stubblejumper]

congrat's... your way work's for you with your brass, your dies, your bullet's, your enviroment, your rifle's and there's possibly alot of other people out there who get away with doing it that way.

And as I already posted,Barnes themselves does not recommend crimping bullets less than .375".I guess that they just don't know any better.

 

[270 totheend]

Back to the question

We seem to have gotten away from the original question.
I also use the same method as Supercub but instead of pencil marks on the rod I use sliding metal bushings, with set screws, on the rod. When I take the first measurement from the boltface I slide the bushing up against the muzzle and lock it down, I then push a second bushing up against the first and lock it down and remove the first one. This retains the position of the measurement but reverses the face for measurement later. The third bushing I lock down when I am pushing up against the bullet in contact with the rifling. Using a vernier caliper I measure the outside distance between the second and third bushing. I have found this to be the most accurate method for me and is repeatable within 0.001" for me. For the tip of the rod I have a metal screw ground flat on the tip.


270 totheend

 

[KODIAK BEAR]

We seem to have gotten away from the original question.
I also use the same method as Supercub but instead of pencil marks on the rod I use sliding metal bushings, with set screws, on the rod. When I take the first measurement from the boltface I slide the bushing up against the muzzle and lock it down, I then push a second bushing up against the first and lock it down and remove the first one. This retains the position of the measurement but reverses the face for measurement later. The third bushing I lock down when I am pushing up against the bullet in contact with the rifling. Using a vernier caliper I measure the outside distance between the second and third bushing. I have found this to be the most accurate method for me and is repeatable within 0.001" for me. For the tip of the rod I have a metal screw ground flat on the tip.


270 totheend

I like your method, particularly the bushings on the rod. Where on Vancouver Island would you buy them?

 

[SuperCub]

We seem to have gotten away from the original question.
I also use the same method as Supercub but instead of pencil marks on the rod I use sliding metal bushings, with set screws, on the rod. When I take the first measurement from the boltface I slide the bushing up against the muzzle and lock it down, I then push a second bushing up against the first and lock it down and remove the first one. This retains the position of the measurement but reverses the face for measurement later. The third bushing I lock down when I am pushing up against the bullet in contact with the rifling. Using a vernier caliper I measure the outside distance between the second and third bushing. I have found this to be the most accurate method for me and is repeatable within 0.001" for me. For the tip of the rod I have a metal screw ground flat on the tip.


270 totheend

Very good idea!


.

 

[Boomer]

Folks are free to do as they like, but if a bullet can move under the force of a kinetic puller it will move under the force of recoil. Seating a bullet forward to reduce the jump to the lands will indeed improve accuracy in most rifles, but so does crimping, because it produces the same uniformity. But old wives tails can be difficult to overcome, and people often do not wish to add another step to the reloading process. Test the accuracy of both crimped and uncrimped loads, you might be surprised.

If you want a sure way to measure the length from the bolt face to the lands consider the following:

1) run a cleaning rod from the muzzle down to the bolt face and mark the rod with a piece of tape at the muzzle,

2) push a fat based bullet backwards held tight to the lands (a small wooden dowel works well for this purpose) then run the cleaning rod down to the bullet base and again mark the rod with a piece of tape at the muzzle, after the rod is marked the bullet may need to be bumped with the cleaning rod to remove it from the barrel,

3) the distance between the forward edge of each piece of tape equals the length from the bolt face to the lands, record that length in you load data,

4) firmly push the bullet of your choice nose first into the muzzle of the rifle then turn the bullet to scribe a line on the bullet,

5) assemble a dummy round matching the length from the bolt face to the lands to the length of the cartridge from the head to the line scribed on the bullet, then seat the bullet slightly deeper into the case until you are at your desired length off the lands, Record the OAL in your load data and keep that dummy round so you can quickly set up your seating die in the future.

 

[SuperCub]

Folks are free to do as they like, but if a bullet can move under the force of a kinetic puller it will move under the force of recoil. Seating a bullet forward to reduce the jump to the lands will indeed improve accuracy in most rifles, but so does crimping, because it produces the same uniformity. But old wives tails can be difficult to overcome, and people often do not wish to add another step to the reloading process. Test the accuracy of both crimped and uncrimped loads, you might be surprised.

Can bullets w/o a cannalure be crimped?


.

 

[stubblejumper]

From Sierra.

http://www.exteriorballistics.com/reloadbasics/crimp.cfm

Throughout the rest of this discussion, bear in mind the fact that not all cartridges will require a crimp of any kind. For those cartridges which can be loaded without resorting to a crimp, we recommend omitting this step altogether.

Neck tension alone should be enough to prevent this from occurring, without resorting to excessive crimping. We regard this as a poor solution to an easily cured problem. Still, many reloaders do attempt to increase neck tension through the use of a tight taper crimp, with varying degrees of success.

Can bullets w/o a cannalure be crimped?

From the Sierra link.

Remember, bullets that do not have a cannelure but need to be crimped should be given a taper crimp.

 

[Boomer]

Can bullets w/o a cannalure be crimped?

.

Folks who use the Lee factory crimp dies claim they can crimp without a cannelure, but I don't do it. In previous discussions on this subject I raised concerns about creating a change to the center of gravity of the bullet in relation to the dimensional center of the bullet, but I was told by those who follow the practice with the Lee Factory Crimp die that my concerns were groundless based on their observations that indicated there was no change in accuracy. I use the Lee crimp die to crimp handgun ammo because I like the resizing feature that ensures reliable feeding, but I use the crimp feature of my RCBS and Redding seating dies to crimp rifle ammo, so I stick with bullets with cannelures.

 

[stubblejumper]

but I was told by those who follow the practice with the Lee Factory Crimp die that my concerns were groundless based on their observations that indicated there was no change in accuracy.

No change?So crimping did not improve the accuracy?

 

[Boomer]

More importantly, using the Lee Factory Crimp die to crimp a bullet without a cannelure apparently did not diminish accuracy.

 

[stubblejumper]

More importantly, using the Lee Factory Crimp die to crimp a bullet without a cannelure apparently did not diminish accuracy

Even more importantly,crimping did not improve accuracy,contrary to your previous claims.

 

[Chip]

More importantly,

A fellow came on asking an innocent question, and this thread has turned into a dink slapping contest.

I too was interested in getting some good advice, but now this thread is just silly.

 

[Boomer]

Even more importantly,crimping did not improve accuracy,contrary to your previous claims.

If you are looking for a fight, I'm not interested. The point of the comment was that there was no loss of accuracy when a bullet without a cannelure was crimped with a Lee FCD, when both bullets were seated to the same OAL. Whether you choose to accept it or or not, crimping serves the same purpose a seating the bullet closer to the lands with none of the disadvantages. I'm done.

 

[stubblejumper]

Whether you choose to accept it or or not, crimping serves the same purpose a seating the bullet closer to the lands with none of the disadvantages. I'm done.

Perhaps in your opinion,yet Sierra and Barnes both advise against crimping for most cartridges and uses as per the links that I posted.So I guess it's up to the individual to read the information provided at those links,and then decide for themselves if they find your opinion more credible than the recommendations given by both Barnes and Sierra.

 

[Siggy Stardust]

Whoa!

Thanks so much for all the timely and helpful responses gang! Many great ideas here that I plan to put into action ASAP for all my rifles!

The answer to this question has eluded me for years as it seemed that anyone I asked just kind of glazed over and shrugged their shoulders...

The help is very much appreciated and I'll be sure to let you know how things work out!

Thanks again!

 

[Chip]

Does anyone use the Sinclair OAL tool? The one that feeds in through the back of the action with the bolt out? Any good?