I've been using the same ~100 pieces in my 257wby since i got the rifle in 2008. Over the past year or so I have noticed a drop in accuracy. The rifle has shot a few groups in the .6-.9"@100, but has shot several groups at 1/2 moa to and past 500. I'd say its accurate, but not a rack driver.

I'm using the same load that I always have (r25, 100ttsx, f215gmm). Primer pockets are tight, brass has been trimmed.

I'm looking for ideas here as I love this gun but have been loosing confidence in it. While sighting in today, it was shooting ok, not great but ok. Dialed the turret to 600 and splattered a rock dead center, so that helped.

You complaining or trying to brag?

How many loads on the brass? The necks may need annealed. Has the throat of the barrel moved forward much? You may need to adjust your seating depth.

I'm asking a question. This is a full custom rifle, with what I consider acceptable, but not exceptional accuracy to start with. Now, the same load that was ~.75@100 is now more like 1.25-1.50@100. Trying to figure out why.

One of my down falls has been that I have not separated the brass so it is hard to say how many loadings.

The bore has not been scoped, I believe the round count is 357 on this rifle.

I will try annealing, that brings back the softness to the brass in the neck, shoulder right?

Annealing will softened the work hardened neck area,and especially if the cases have mixed numbers of loads it should promote uniform neck tension. I'd suspect you would find the throat for that chambering moved forward a fair amount by this time. Do you have a starting distance to lands measurement to compare to?

If you shot all 357 rounds on a single afternoon, the barrel might be suspect, but over a five year period it's not likely much more than broken in. Unless your loads are well above max, the brass is also not a likely culprit.

I have played with a couple of Weatherby's for a almost 20 years. They belong to a friend. One is a .257 Weatherby custom job with a Douglas barrel and Sako action in a quality synthetic stock, the other is a .300 W original made in Germany with a classic Weatherby walnut stock. Both were exceptionally accurate, until a couple years ago. They went from MOA to 4-5MOA shooters. After asking a couple questions, it seems he had started using Frog Lube on the bores.

He was never a religious gun cleaner, and typically pushed a couple patches of Hoppe's down the barrel after each season. Somehow the combination of minimal cleaning and the Frog lube was a non-ideal mix. A thorough cleaning and they both returned to normal.

It wasn't the first time a good cleaning had "fixed" an accuracy problem for me.

I would start with a good copper remover like wipeout. You can leave it in overnight. While it is soaking, I would examine your brass.

100 pieces of brass and you BELIEVE the round count is 375. You don't know how many times each was reloaded. Hmmm, let's see. Since you believe it may be 375 shots, let's call it 400.
400/100 = 4 reloads/brass

But since you did not separate the brass, that means it could be north of 5 or 6 or 7 reloads. It may be time to anneal or try a box of new brass and see what gives.

Don't forget you are dealing with a hotrod.

I am a pretty religious cleaner, so I do not believe that to be the problem.

I don't know why I said I believe there are 357 shots, I have kept maticilious records on this gun and KNOW there have been 357 rounds down the pipe.

Been using Norma brass in a hot rod 220 Swift for a good number of years now, and Yes it does wear out. Norma is a bit softer than most other brands on the market, and tends to allow more reloads before annealing is needed. I have as many as 10 reloads on one set before I have had to anneal, so don't think 4 is excessive.
I never use a whole 100 bag, tends to cause confusion as to the number of reloads on each set. I will split it into 25 or 50 lots, and just keep working with that lot until it wont go anymore.

Having said all this, I have found that annealing will help for a short time, but if running max or over max it wont help much unless you are very adept at the process so that the necks are tensioned the same.

As one other poster mentioned, I would lean towards a fouling issue. Throat erosion could also be part of the groups opening up as I have learned from the Swift ( and yes, throat erosion on a hot rod in under 400 rounds is definitely plausible). Unless purchased in 8lb keg, lot to lot variation of the powder can also cause your problem.

If the groups have opened suddenly, check the crown.

If this was ammo that was stored for a while is it possible the bullet took a "set" to the brass. If it did velocity can jump over normal loads and your old recipe is now null and void.
Been there done that before being very careful to clean all sizing lube from inside necks before finishing up the ammo.

Kraky, I have shot old loads and new with the same results.

The crown might be a good spot to check. Also, I just had it cerakoted, so the action/bedding fit is snug as a bug in a rug.... Although the groups were opening up before that.

Bet it comes down to cleaning doctrine. Ten to twenty reloads ought to definitely wear anyone's brass out.

Anneal the brass. If the cases have been fired a different number of times, the necks will produce different amounts of bullet pull--and even if they've been fired the same number of times, the necks will be harder.

For the finest accuracy, many target shooters anneal brass after EVERY shot.

John, thanks for the advise.

For arguments sake I have loaded up some other loads (that have been proven to shoot) with virgin brass.

One thing I am wondering, is about the recent cerakote job, making the bedding, recoil lug etc fit change.

I hope you don't have to change its name from Chupacabra to Chupaverga.

I was going to chime in with annealing also as I think that is your huckleberry! I anneal after every three firings via candle method.

I doubt the coating has any bearing on this. Tackle one thing at a time starting with annealing.

Good luck!

I feared Cerakote might be a little thick for already well-bedded rifles, but my suspicions haven't proven valid so far, in several rifles. All bedding compounds shrink a little bit as they cure. Some shrink more than others, but apparently it's just enough to accommodate a layer of Cerakote.

Is the barrel free-floated, or have some form of contact bedding?

the only thing that really caught my attention as to the space because of the extra layer, is the fact that getting the rifle to sit in its place in the stock it was difficult and removing it was even harder so.

it is free floated up until the taper for the chamber.

Jake if I name it that I'll just give it to you and it'll fit right in.

what is the candle method?

Use a candle as the heat source. Hold your brass in your finger tips in the web area. Rotate brass neck, shoulder and a little past the shoulder in the flame.

The idea is when the brass to warm to hold, it's done!

I use a damp cloth to wipe it down right after I pull it away from the flame to cool it down and remove the carbon.

The goal is to apply heat, but not too much down at the case head thereby reducing the probability of case head separation.

I took this method from Mule Deer.

My 257 was more consistent floated to the lug. I normally bed a pad under the chamber on all rigs, but this one was a head scratcher. I took a cheap stock and messed with until I found consistency, went back to the original stock and removed the chamber pad, and all was well. Might be something to try if you have a cheap stock to tinker with.

I do not have another stock. But the thing is is this gun has been issued her before. I reviewed my notes this weekend and have made a few loads that shot in a .5 .6's,.With Virgin Brass This Time.

So I used the candle method on 15 pieces today. The thing I noticed, is once I wiped off the soot, there was no visible signs that the brass has been annealed. While looking on youtube, I saw several demonstrations of guys doing it with torches and I noticed the neck turned and seemed to stay blue. Is this something I would expect with the candle method, or does the higher, quicker heat of the propane torch cause the blue and I should not expect it?

The neck turning blue often indicates the brass was heated too much. This happens a lot when annealing with torches.

Gotcha.

That is good to know as the 2 videos I watched said to make it turn blue, but not red.

On a side note, I had a separation in my sizing die... That's gonna slow the process down as I am sure I will have to send it to Redding to get fixed.

Factory LC match and Lapua brass I have has pretty good color to it, and when I've stovetop annealed I've gone for the same color. Maybe I've overdone it.

I just sold 34 boxes of newLC .308 match ammo, and it had the blue neck on it. So did 1000+ rounds of once fired brass.

Much can be debated over annealing. But it is very easy to go too far and ruin your brass. Click on the link for a good read keeping in mind the the temp of a candle flame is about 800 degrees.

Link