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Extreme Spread with 338 Hart (338-300 ultra, edge)

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Unread 11-26-2010, 09:17 AM
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Join Date: Nov 2008
Posts: 215
Extreme Spread with 338 Hart (338-300 ultra, edge)

I am not having the best luck this year with anything shooting related, anyway. I am shooting the above rifle and had some baffling results yesterday.

I was shooting 300 grain bergers .020 off with 93 grains H1000, and cci 250, numerous times, I have shot this load and it has never shown any sort of pressure signs. Well yesterday, I fired 10 shots over a period of time. The first say 7 there were no pressure signs, then the last 3 had extractor marks. Also, my velocity seemed low, around 2810, with a 34” barrel. And my extreme spread was terrible at 60 fps. I am wondering what the problem can be? This is a new 8 lb container of H1000. Last year, with 300 smk’s, I was getting single digit ES at 2950 fps. That was with a smaller container of powder though. Same lot of primers. Each charge is measured on an rcbs electric scale.

So here are my questions, can the powder lots be that different?

Can the bergers be doing something different than the smk’s?

Can the electric scale be off?

When I have done load development the velocities usually correspond and go up each half grain or grain of powder increase, and this spread was higher than the powder increase of 1 grain usually.

I am just pretty baffled by this.

Another note about my sizing, I was using a full length bushing die, but I found that it worked better when I used the expander ball again due to the necks having a lot of carbon when only the bushing was used with no expander . But lately, I have been only neck sizing, I felt I was working the shoulder too much when I did not have to full length sizing.

Can this be as simple as I should use the bushing die again with no expander, and not size the whole neck as not to hit the shoulders and see what the ES is? Or is there something else I should look at first?

actually, I thought about it some more, and the bushing die shoudl not matter, as I got this single digit ES from virgin brass, and I used the expander to open it up then bushing, then expander on the way back out, so my statement above may not hold water, figured I should add this in, will help answer that question atleast.

thanks for responses in advance.

Last edited by timeless61; 11-26-2010 at 09:27 AM.
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Unread 11-26-2010, 09:42 AM
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Join Date: Feb 2008
Location: IOWA
Posts: 2,123
Re: Extreme Spread with 338 Hart (338-300 ultra, edge)

Am I to understand that you are using the same load with the 300 Berger as you had been using in the past with the 300 SMK without doing load developement for the 300 Berger?
If so, you need to back up, start over with load developement for the 300 Berger. Anytime you change a component of your reloading, plan on starting from square one.
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Unread 11-26-2010, 09:56 AM
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Join Date: Sep 2004
Location: Nevada
Posts: 810
Re: Extreme Spread with 338 Hart (338-300 ultra, edge)

I agree with the above post. An example was the home tumbler moly coated bullet rage of about 15 years ago. It caused the bullets to slide down the barrel so easy that they lost velocity. So it took more powder to get the same performance.

Between bullet manufacturers the hardness of the copper content could change. Or the amount of bullet to barrel contact surface area.

From what you stated about extractor dings. I would shift to a slower powder from the burn rate chart with an equal gr. for starters and then adjust
.270 Ackley improved 29 inch 1.250 dia. target barrel 7mm STW 28 inch 1.250 target barrel. I also love my .458 mag for varmints and the biggest game in the world.
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Unread 11-26-2010, 10:00 AM
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Join Date: Nov 2008
Posts: 215
Re: Extreme Spread with 338 Hart (338-300 ultra, edge)

no, my loads are different, I did basically what I did for the SMK, my load development was not too crazy for it, find my max and back off some, and it always yielded single digit ES with the smk and older powder, at every velocity because I shot the same string of charges on different days, and still each velocity was within single digits of each other.

now, the bergers, I did not shoot each load through a chronograph when finding my max, I did not have a working chronograph at the time I measured the cases, and I am now reloading for useful case life, which is 94 grains max with the berger and 93 grains max with the smk. so i backed off some, but am just baffled by the ES comparing it to load development for the smk.

with the smk as I said even on different days every powder charge was very close to the same charge's velocity on a different day. also, my pressure signs on a load that I know is nowhere near the top max, let alone not even max where I had case expansion. on this rifle and others, my cases expand before I even show any pressure signs, and there was a direct correlation between the case expansion and primer pockets loosening too much so that is why I am loading like I am currently.

maybe I just got extremely lucky with the SMK, I am not sure, I just read a bit about the bergers on here, and most people were getting the same performance with the berger as the SMK, with different charges still, but the H1000 and cci 250 combo was working well.

Last edited by timeless61; 11-26-2010 at 10:04 AM.
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Unread 11-26-2010, 10:54 AM
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Join Date: Oct 2005
Location: Wyoming
Posts: 382
Re: Extreme Spread with 338 Hart (338-300 ultra, edge)

Do a search. Me and a lot of others have noticed a difference in the new lots of H1000. I used to shoot 93 grns under a 300 grn SMK but now I get pressure at 89 grns., less velocity and worse ES. I switched to the Bergers and I'm not seeing pressure at 89 grns and haven't tried going any higher yet because that load shoots so well.
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Unread 11-26-2010, 11:18 AM
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Join Date: Nov 2008
Posts: 215
Re: Extreme Spread with 338 Hart (338-300 ultra, edge)

I searched some, and read a bit about the newer powder, also looked back at my notes, and as I thought, every charge, just not the charge i decided on with the smk's and old powder was single digit ES i fired the same charges on different days 3 times and all the velocities were within single digits of each other. I doubt that is a fluke, so I think it is the new powder, I will try something slower to try to take advantage of my longer barrel. I used H1000 initially because the ES was great.

Last edited by timeless61; 11-26-2010 at 03:46 PM.
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Unread 11-26-2010, 04:41 PM
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Join Date: Feb 2004
Location: Pennsyltucky
Posts: 2,630
Re: Extreme Spread with 338 Hart (338-300 ultra, edge)

i have 2 rifles in edge chambering and pulled the big one into action this year which hadn't seen any last year. i shoot H1000 powder with 250-300 gr bullets. on one of my first few shooting sessions, maybe the third, i had a shell that didn't go off. thought it was a weak firing pin spring as i've had this before. but it wasn't. took the shell apart, and the primer went off but didn't ignite the powder. the bottom one third of the powder was blackened and clumped together. the rest looked normal. a couple weeks ago, mayb70-80 rounds total, another didn't go off. it looked the same as the other one that didn't go off. i'm using 215 primers, and H1000 from an 8 lb keg that i bought last year and never used till this year. havn't shot either of my big guns hunting this year, been long range hunting with my trusty ole 30-06. i was also getting very high spreads, 50-60, and poor accuracy,which i hadn't in the past.
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