Help me figure out why I'm blowing primers

[nksmfamjp]

I blew primers with 81 grains of 7828.

That is about 4 grains over max per Hodgdon....yep blown primers.

 

[nksmfamjp]

I never saw any signs of pressure. All of the primers looked exactly like the lowest load and or my fired factory rounds.

Fired factory rounds are all loaded at maximum safe pressure with new brass. New brass reloads should have about the same belt diameter as your factory belts. You need a good micrometer for this. 0.0000 is fine.

 

[lotech]

Is your case length trimmed to spec? How about neck diameter? Is it too thick?

 

[smithjasona1978]

This is all brand new Hornady brass. CCI 250 magnum primers. Primed with a Lee auto prime. I shot a couple dozen rounds yesterday. That's all my shoulder can handle in one sitting. No more blown primers. I left the oal the same and backed the charge off 3 grains. Accuracy isn't getting any better yet. Rifle is fine though. It groups Weatherby factory ammo at about an inch when I am in the mood to try hard.

 

[wonderman4]

I am going to get snotty on you.

First, you already admitted to being a "noob". Your word.

Second: you do not seat primers flush. They are seated 0.003"-0.005" below flush (in other words recessed).

Third: you are taking it for granted that your chamber has a 0.361" freebore.

How the hell do you know if you haven't measured the chamber from the bolt face to the lands??

Fourth: a newbie blowing primers is as dangerous as playing catch with hand grenades as has been proven by your actions.

My suggestion is to back off from the loading bench or whatever you use and do some research by reading a couple of loading manuals and get a copy of the "ABCs of Reloading" and read the book thoroughly, then read it again.

https://www.amazon.com/dp/1440213968/?tag=lrhmag19-20

There is nothing more dangerous than a "noob" thinking he/she knows enough to reload any cartridge when he/she doesn't know enough other than making bombs. Just think of an innocent bystander or someone sitting on a shooting bench next to you when you launch the bomb.

 

[rsnell]

You have not followed the standard reloading procedures. You are doing it backwards. Start with the loading manual of your choice and follow it exactly. The last thing you experiment with is the seating depth. You have already exceeded the maximum pressure in at least one load since you found a primer in the magazine.

If you do not understand rimmed, rimless, and belted cases as will as head space, you need to read the beginning chapters of one of the reloading manuals.

 

[Flare]

One of the best things I ever did was read through a reloading manual several times before reloading the first time. I also worked up slowing in .5 increments to the max and stopped there.


One other possibility is you have a carbon ring built up and that's causing your pressure spikes I've had that before

Corey

 

[sentry53]

there are people on here that have reloaded longer the I have. the seven rem mag and the 300winchester mag the neck will grow around 7 to 10 thousand on the first firing on factory ammo. I have four weatherby rifles every one has will shoot better after about 100 rounds. I use the reloading book from the bullet maker for all. every one of them are just short of book max are the best loads.

 

[Tiny Tim]

I am of the understanding that Weatherby rifles have a large free bore to allow a large bullet jump to keep pressure down. While loading the bullet further out on standard cartridges has a tendency to reduce pressure by increasing volume, it only does this to a point. Then pressure will begin to increase. It is possible that given the Weatherby design, that you are getting that same effect without actually being too near the lands. The need for this close seating is generally only needed with a particular type of bullet, and that only for accuracy. Other bullet types are far less sensitive to seating depth and can give exceptional accuracy with relatively large jumps to the lands
And as others have stated, you appear over the max listed charge for the cartridge.

 

[LongestShot]

You're starting off way too hot. You are new to reloading and don't appreciate the detrimental results you can have from a load that's just too hot. Stiff bolts and blown primers are the last warning before a caustrifiic result happens. Go back and start at the beginning. What I mean is factory length cartridges and powder loads that are nominal. Start from the beginning and move up one step at a time. You are very close to having an entire receiver blow up in your face. This is a very dangerous hobby. Reloading takes years to perfect. Mistakes can be fatal. I suggest that you find and older experienced reloader to work with you. They have years of invaluable experience that can save you from making rocky mistakes.

 

[jeffwhitcomb]

I'd be curious to know what increments in powder charge increase you were using while working up. With 75 rounds loaded, multiple powders used, and an above book max charge that blew primers indicates potentially that the increments may be in grains instead of tenths of a grain. Might be wrong on this logic but I would recommend increasing charges in .3 grain increments as potentially a large increment took you from no pressure to very dangerous pressure with no middle ground to start giving you warning signs.

 

[betolatinlu]

So how does everyone on here shoot rounds loaded longer than max coal?

By loading them one at a time .

 

[smithjasona1978]

I guess that I need to start all over and be more specific about what is happening here. I bought a new 300 wby. I bought a full set of reloading dies and components for it. I also bought 5 boxes of Weatherby 180 grain ammo. This I used to get my scope zeroed and break in the barrel. Best group was .77. And I got a string of 7 at 1.08. Rifle is good. Next time I went to the range I took my first set of hand loads. New Hornady brass. CCI250 primers "I do not measure how deep my primers are. " I use the priming tool exactly as the instructions say.
My first set of loads were.....
New tumbled Hornady brass full length sized and trimmed to the length of the shortest case that came in the box of 100. I don't remember the exact number. I have it written down but I'm not at home. 2.817 I think. All rounds loaded to oal 3.56. All of my load data come from Hornady 10 edition.
Loads were 3 of each charge
IMR7828
74.0, 74.4, 74.8, 75.2, 75.6, 76.0, 76.4, 76.8
MAGNUM
80.0, 80.4, 80.8, 81.2, 81.6, 82.0, 82.4, 82.8
R33
84.0, 84.4, 84.8, 85.2, 85.6, 86, 86.4, 86.8

Most accurate load of the first batch was 1.52 at 76.8 of 7828. Basically the rest sucked. I worked my way up at .4 g on ALL loads. My second trip to the range took me up to .4 above max on magnum and 7828. And max load on r33. Still no accurate loads. So my 3rd trip to the range I loaded the exact same set as the first trip loaded at 3.65 oal. The 4th trip was the same as the second loaded 3.65 oal. On my 4th trip, suddenly the groups started to tighten up at the high end of the magnum and 7828 loads but the best group was the. 4 above max load on both. R33 showed erratic accuracy and low velocity.
So my next trip I loaded the same loads as the first trip at 3.75 oal. All groups opened up and all velocities dropped significantly. So my next trip was the loads that I listed at the beginning of the post which I'm not typing again that blew the primers.
And to the one who asked I know my freebore is .361 because I measured it with a digital caliper and bullet and fired case 4 times. Oh and also that is what Weatherby says it is. . Got .361 twice. .362 once, and .360 once.
So in conclusion I went through the upper 2/3's of the load list from 10th Hornady with the powders I have, and never got close to factory Weatherby 180 grain factory loads.
My apologies for not being more concise in the beginning. I was going for brevity.

 

[Mike Matteson]

By starting low and working up, not running an extra 2 grains cuz theres room. I dont know anything about weatherbys, but I do know I start at a safe low charge weight and work up to higher