Help me figure out why I'm blowing primers

[aushunter1]

The aim of reloading imo is to find accuracy nodes not to try & get the most velocity as possible out of the process.
In the case of having excessive freebore & seating into the lands not possible then the ideal seating depth would be either whatever fits your magazine OR at a depth that still allows the projectile to be held securely in the case mouth.
Whatever OAL you choose you need to set that before starting the ladder test, after you get a decent grouping you can start changing the CBTO in small increments.

Also as someone else pointed out if your primers are not seated to a correct depth then they would be more susceptible to blowing.
I always uniform the primer pockets before loading, even on new brass!
Uniforming evens out the pocket depth, not the side walls so you can get maximin depth during seating.

In addition all primers are not equal, some have slight variance in their cup thickness & cup diameter.

Another thing to check is if you are getting extractor marks on your headstamp area, if you are you are definitely over pressure!

https://www.accurateshooter.com/technical-articles/primers-and-pressure-analysis/

 

[LoneTraveler]

Every Weatherby made rifle I have dealt with has excessive free bore. . Roy Weatherby designed that into the rifles back many years ago so he could get velocity with the available powder of the time. H 4831 was the slowest market powder available to reloader in that era.
Case neck thickness, Case length, and distance from diameter on bullet ogive to rifling in the barrel all have affect on pressure.
Most reloading books state, Their printed loads are to be used only in Weatherby rifles because of the free bore in their rifles. The reloading data is based the OACL they post with the bullet being used.
Go by the loading books and be safe,

 

[yorke-1]

I gave Vel. Fpe. and grains of bullets. I also stated primers and types. I didn't give grains of powders. I did state increase rate of increase on larger cases that hold 70 grains or more of powder to start with. After shooting the max load given by the reloading manual Then working on these loads, I started out with .1 of a grain after shooting the high powder load in the manual. Have any ideal how long it takes to get to max powder loads with different primes, cases, bullets. Especially loading 5 round sets. Equals 250 rounds. Then there change of bullets, and primers. That can take you beyond the barrel life. So then you start all over again with a new barrel to figure best load, Vel, FPE. for groups. Then down range to target out to 500 yards. I am not a long range shooter out to 1000 to 1200 yards. In those days we didn't have range finders. We had to get out with a chain and do the foot work to determine actual distant. There wasn't rifle ranges where I live back then either.

My late friend and I have discuss loading info with the people that write the reloading manuals.

The other is I am Graphic Dyslexia so the command of the english lanuage and detecting mistake is very hard for me. I do my best.

He was giving problems and others may run into this again. I also stated take the rifle to the gunsmith too, with case and primer in hand. I have seen bad head space, cut cases in both rifle and shotgun. I have seen where people mixed up shot bushing with power bushing, and the effects of them.

Long cases also create high pressures, wrong primers can create major problems. Not to forget, bullet extending into the rifle lands.

The hole ideal is to: getting the bullet started into barrel and still being held by the case neck then down the barrel to the target. I had to start by blacking the bullet to determine where the the lands were. In the olden days. Back in the days there wasn't many thing to cut necks.

I have work on loads with 223, 5.56x 45, 220 swift, 243, 25/06. 270, 6.5 x 55, 264 Win Mag, 7mm Rem Mag, 308, 30/06, 308 normal mag, 300 win mag, 300 H & H Mag, 338 Win Mag, and 375 H & H Mag. Not to mention a 22 mag that I had to cut out over 1/8" out of the forearm of the stock to get it to group. Setting down from a 3" + group to under an 1" at a 100 yards.

Most stock I build myself, being that I am left hander.

On the 500 Smith loads now are stated powder loads and primer in reloading manuals. that why that info was given out.

Mike

I assumed that your grammar was a result of either Dyslexia or possibly English being a second language for you.

My concern is with the data you're throwing out there. Some of the numbers you're giving for a 24" 338 Win Mag are so far outside the realm of realistic that they're either incorrectly typed or horribly over pressure. If you're getting a 200gr bullet over 3200 fps from a 24" 338 Win Mag, you're WAY over pressure. That's 338 RUM territory and well beyond any published load data I found for Win 760 powder in a 338 Win Mag.

It's very common for inexperienced reloaders to chase velocity and not be able to catch numbers which are clearly inaccurate or unrealistic. If somebody tried to reach the velocities you posted in a 338 Win Mag with Win 760 powder, things would not go well.