Am I about to blow my face off?!?

[AJ Peacock]

Hey AJ,

Thanks for the info...would you mind explaining "crush fit"? I have read the term here before but not sure exactly what it means.

Ryan

After you reload the same brass a number of times (sometimes just once if it's a hot load or real soft brass) and don't full length resize it, the case will stretch enough that you will actually be 'crushing' the cartridge a couple thousandths between the shoulder and the head.


A crush fit is believed to be a more 'perfect' fit between the chamber and the cartridge. I've personally never had my best accuracy using that method. It may be that I am crushing it too much? Or maybe it is more applicable to typical 'smaller volume' BR type cartridges? I tend to lean toward the larger cartridges, with my light deer rifle being a 7mm Rem Mag and my varmint rifle being a .243 Win.

Hope that explains it,
AJ

 

[baldhunter]

I ran into the same thing when I was loading some 165gr Hornady Interlocks in my 300WSM.COL showed to be between 2.840-2.900.I seated the bullets down to 2.810 because it touched the lands at 2.820.I tried some 165gr Hornady SST and they touch the lands at 2.880 so I set them at 2.860.I was thinking my rifle had a really short throat but it was just the shape of the bullet.

 

[Iron Worker]

Can't remember what issue but Varmint Hunters magazine printed a study of the merits of neck sizing over FL sizing . Concerning our hunting rifles. They produced evidence that it was necessarily more accurate. I shoot a 6x284 and a 22-250 AI I've FL same brass many many times and still have plenty life in them. Now mind you I anneal this brass also now that is a must.

 

[Iron Worker]

BTW what caliber are you loading for? Your shooting 200 gr Accubonds? in what a 308 ? 300 RUM ? That matters ! We know your not shooting a BR type rifle.............

 

[AtownBcat]

Im shooting a 300WM. I had to use the BR-2 primers because thats all I could find. I realize they are "large rifle" primers but not "magnum". Could some one explain what difference I would notice if I had some magnum primers? Thanks.

 

[AJ Peacock]

Im shooting a 300WM. I had to use the BR-2 primers because thats all I could find. I realize they are "large rifle" primers but not "magnum". Could some one explain what difference I would notice if I had some magnum primers? Thanks.

You will likely get a bit higher pressure and a bit more velocity. You can very easily get great groups without magnum primers in 300WM size chamberings. If you get a great load, stick with it. If you change to a different primer, please back off your load and work up to it; just like starting over with load development.

FWIW: I use BR-2's in my 300WSM, I use non-magnum rem 9 1/2's in my 7mm Rem Mag.

AJ

 

[AtownBcat]

So wouldn't the use of magnum primers give you a better long range load with better velocity? And I also wanted to know if you can trust the velocity that is published in the manuals or is owing a crono a must? I understand that all the long range drop tables use velocity....well you see where im going.

 

[AJ Peacock]

So wouldn't the use of magnum primers give you a better long range load with better velocity? And I also wanted to know if you can trust the velocity that is published in the manuals or is owing a crono a must? I understand that all the long range drop tables use velocity....well you see where im going.

You can pretty much run the same velocities with magnum or non-magnum primers, in my experience with the 7mm Rem Mag, it just take 1/2 - 1.5 gr more powder to get the same velocity. In fact I've used the non mag primers and more powder to get better velocity (more consistency) than with the mag primers in MY RIFLEs.

A good chrono is a great investment and the best tool you can easily use to keep an eye on your pressures. As long as you are using appropriate powders and keeping the velocities in line with the listed velocities from reloading manuals, you can be confident that your pressures are not too high.

I use the CED Millenium II crono with the IR sensors. It works great.

Knowing what YOUR velocity is, makes creating good drop tables MUCH easier.

Here is an example for you. Dogdinger and I both shoot the same EXACT loads in our Edges. The same powder, primer, bullets and seating depth. His Edge shoots 50fps faster than mine over the same Chrono. Both barrels are made by Pac-Nor and his barrel is SHORTER than mine. He just has a 'faster' barrel! They are both VERY accurate.

Knowing YOUR velocity is very important.

AJ

 

[41mag]

Having your own or access to a chronograph is great, and will or would be a great aid in working up and testing your loads. However for the time being, and depending on how far you actually intend to shoot, if you stay within the parameters of listed loads, and are not noting typical pressure signs, you can also do drop test to determine fairly close to what your loads are doing as well. It might take a little playing around with one of the calculators but you can get a decent ball park figure.

The number one key to a good long range load is accuracy first and velocity second. If you hitting 3200fps with your load but shooting 3" groups at 100yds, verses 2900 and 1/2" groups, you can see the differences as you would stretch these out to longer ranges. IF you have access to 300 - 400yds of open area to shoot across, take a piece of plywood or large piece of cardboard with butcher paper stapled down the middle. Post a stick on target a couple of inches form the top and start at 100yds and work it out in 50 or 100yd incrememnts. Aim at the same spot ever time and you will get your drops. Shoot a couple of rounds at each range for group and verification. When your done you can compare these drops to ballistic tables on one of the programs.

Even if you don't have a chrono or access to one, you can still build an accurate drop table from this method. I did it for several years before actually getting my own chrono. However nowdays one of the cheap Chrony's is still better than a stop watch when determining velocity. It might not be as accurate as one of the Oehlers, but it will get you well withing the ball park without a lot of cash outlay.

Good luck with your loads and enjoy your finished products.

 

[baldhunter]

If you're reloading,I'd get a chronograph.They are not that expensive,around a hundred dollars and you can really see what kind of velocities and how consistent your load velocities are.It is a great tool.As far as advertised velocities go,some are just that and then every rifle is different too.My old Lyman books from back in the mid 60's seem to match my velocities closer than some of the newer stuff and I usually get a little lower than what is published most of the time.

 

[gunpower]

Once you find the oal you should then make up a dummy round and keep it for future use.

 

[BountyHunter]

Guess I will differ on benefit of NS only vs FL size, particularily with magnums.

You may or may not get better accuracy and if so it will not last by NS only. After repeated firings the brass stretches where it is tight to chamber. You will not get peak accuracy there. at that point it has to be FL sized or throw the cases away. The worlds record 1000 yard group (5 shots in 1.4 inches) was shot with brass that had been shot a documented 54 times in a shortened necked down 338 Lapua. That same brass was shot over 80 times before discarding. It does not get any better than that.

If there is a problem with FL sizing it is that many do not know how to properly adjust the dies to where they are sizing the body and only bumping the shoulder .001-.002. Therefore many of them say NS only.

If you follow the instructions that come with the die, you might bump the shoulders back .008 and get case stretch and head separation eventually. Learn to properly adjust your FL dies and you will never NS hunting rounds, in particular. Properly adjusted FL dies save brass, gives uniform brass dimensions, does not over workd the brass and most competitive shooters think gives better accuracy.

It makes no sense to me to have a round that is too tight to smoothly chamber in a hunting rifle (in particular) without fighting to close the bolt! One grain of dirt and your are SOL.

Now if you are just enamored with the idea of a partial neck size to center the round (that is called a false shoulder and used to fireform brass to wildcats primarily) then NS first and buy a Redding body bump die ($25) that will size the body and push the shoulder back while leaving the false shoulder.

Primers can and do change the accuracy and pressure substantially. Not always is a magnum primer the best primer to use. Try both magnum and non magnum.

With a chrono you can spot your ES and SD with the best loads and primers for peak accuracy. For LR work it is a must have tool.

BH

 

[Iron Worker]

My Chronograph has told me that published velocities are crap. Many times loading a published max load velocities were way lower then published..... SD and ED or super important. Dang some loads can very 100 FPS and still shoot a decent group at 100 yds but then shoot that same ammo at even 200 yds and you'll see what I mean.

 

[AtownBcat]

Good stuff guys....my computer has decided to die so im sending this between "blue screens of death" hope to be back up mid week. Thanks for all the input!! ryan