ES SD issue

foul bore

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I have a 6.5 PRC that I have done the seating depth process, am now chronographing the loads. I have one load that has one shot that ruined the es/sd also had a round out of a very good group 4 shot .193. I am going to recheck this load to verify. could .005 change in seating depth make a difference ? shot 5 is .414 from group, and 44fps faster. There was a time when 4 out of 5 would have been ok, but the bar has been raised. any ideas or do I need to keep checking, 10 different loads right now . I have learned a lot from this forum. THANKS
 

L.Sherm

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I would start by looking at your brass at least sort by weight.
What brass are you using?
To answer your question yes .005 does make a difference you might not notice that much untill you get out to 500 and beyond.
Different primers can also tighten up E.S
 

foul bore

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I have done everything to brass I know to do, am a firm believer in that process. Hornaday brass was the only one readily available. Have used 2 different primers same charge ect. I just changed seat depth by.005 and revisiting the load in question. if it wasn't for the es I would think it to be the shooter or conditions
 

L.Sherm

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How many firings on your brass? I would anneal the brass work hardened necks can have alot to do with E.S.
They can get work hardened just from the manufacturing process.
 

foul bore

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H1000, and H4831sc Fed 210M, CCI250 mag primer, brass is twice fired. best load is H1000 with cci250 average 2923 fps
 

foul bore

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I will try annealing I did not think it would be needed this early. I sized the new brass and reloaded it twice
 

L.Sherm

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Anneal your brass and then try your best load and see the results.
 

J E Custom

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I have a 6.5 PRC that I have done the seating depth process, am now chronographing the loads. I have one load that has one shot that ruined the es/sd also had a round out of a very good group 4 shot .193. I am going to recheck this load to verify. could .005 change in seating depth make a difference ? shot 5 is .414 from group, and 44fps faster. There was a time when 4 out of 5 would have been ok, but the bar has been raised. any ideas or do I need to keep checking, 10 different loads right now . I have learned a lot from this forum. THANKS

Some barrels foul at 4 to 7 shots and the way I find out when it happens is to clean the barrel good and start shooting and depending on the barrel somewhere near the 4th, 5th, 6th, or 7th shot this will happen and the group will open up slightly.

If you hadn't chronographed the loads I would say that possibly you were trying to hard to get the 5th round in the small group. (It happens to all of us because we don't want to mess a great group with the last shot) I have had the same thing happen to me when shooting 10 shot groups.

Heat also plays a role in this, so let the rifle set for a few minutes between shots and that may solve the problem.

For a hunting rifle this is not to bad, but if trying for the best accuracy, it can be frustrating.

J E CUSTOM
 

Plinker147

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I how Far Are you shooting your groups at? If your at 100Yds a lot of these suggestions won’t make
a difference, 5-600 yds they will come into
Play. If your at 100-200 it’s likely shooter induced.

And that small of seating depth change shouldn’t, make much difference
 
Last edited:

Bang4theBuck

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I would openly cjeck.the case volume of enough cases to get 10 cases that have virtually the same volume. I wouls anneal.the brass, and load all 10 the same. Shoot two 5 shot groups and see what you get.
 

foul bore

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Some barrels foul at 4 to 7 shots and the way I find out when it happens is to clean the barrel good and start shooting and depending on the barrel somewhere near the 4th, 5th, 6th, or 7th shot this will happen and the group will open up slightly.

If you hadn't chronographed the loads I would say that possibly you were trying to hard to get the 5th round in the small group. (It happens to all of us because we don't want to mess a great group with the last shot) I have had the same thing happen to me when shooting 10 shot groups.

Heat also plays a role in this, so let the rifle set for a few minutes between shots and that may solve the problem.

For a hunting rifle this is not to bad, but if trying for the best accuracy, it can be frustrating.

J E CUSTOM
I would bet on heat build up, I will be more patient
 

foul bore

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Feb 1, 2016
Messages
193
Location
texas
I how Far Are you shooting your groups at? If your at 100Yds a lot of these suggestions won’t make
a difference, 5-600 yds they will come into
Play. If your at 100-200 it’s likely shooter induced.

And that small of seating depth change shouldn’t, make much difference
I am using the chronograph at 100, I will be shooting up to 800, in first stage of load development, if I had not had a velocity spike I sure would think it was my error. 4 shots measured .193
 

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