What am I doing wrong

[C.Smith]

I had posted a few weeks ago about pressure issues in my 7mag. Thought I had it figured out but went to the range today and first shot, not even a hot load stuck my bolt closed, blew the primer. All my pressure problems started when I changed lots of RL22, which I thought was my problem but I switched powders and had issues there too. Found out that I was loading a little further out than before, so I seated bullets to what I originally was using thinking that was my issue, but to no avail. Today I had loaded up seating the bullets to 3.295 which is five thousands longer than the book OAL. The only other thing I can think of is I changed lots of Accubonds, I've measured those and they seem fine.

So was using brand new Hornady brass, with 160 accubonds, GM215M primers, and H1000. The load was 62 grains which hit 3000 fps which should have been 2800 fps. I got my hands on factory rounds and they shot fine. So i'm completely lost to what is going on. Barrel was clean no oil in it that i could see. Any ideas would help.

Corey

 

[JD338]

I'm thinking its the brass. If the case capacity is less (heavier weight brass) than it would drive up the pressure. Try weighing a few Hornady cases and compare to R-P or Win brass.

JD338

 

[steve4102]

There is no direct correlation between case capacity and case weight.

If you want to compare head stamps you need to use actual volume in grains of H2O of fired cases.

 

[Dwh7271]

Did I read this right?
You chrono'd the one shot at 3000 and it should have been 28 something?
Could be a hot batch of powder.
Could be lower case capacity in your cases.
Are you absolutely certain there's no oil in the chamber?
No insult implied on any of these, but have you checked your scales?

 

[C.Smith]

Did I read this right?
You chrono'd the one shot at 3000 and it should have been 28 something?
Could be a hot batch of powder.
Could be lower case capacity in your cases.
Are you absolutely certain there's no oil in the chamber?
No insult implied on any of these, but have you checked your scales?

None taken. yes it hit 3000 fps when it should, according to the book been 2800 fps. I had a similar issues or the same one with RL22 using Winchester brass before. In fact ruined all my Winchester brass, hence I have new batch. I was pretty sure there was no oil i the chamber, in fact I fired three Factory new cases before firing the reloads with no issues. If there was would the casing come out oily?

I'm not sure it is the casing either. With the RL 22 I was shooting that load for several years no issue. Ran out of RL 22 and started with new batch, also new batch of Accubonds. Starting load was over pressure. Somehow I had changed my OAL and so I recently changed that back and still the same problem. This is why I'm completely stumped.

Corey

 

[Dwh7271]

OK.
If 62 gr hit 3000 then here is what it looks like adjusting QuickLoad to fit that info. FWIW, I kind of think it may be something else also as I had to really manipulate burn rates and stuff to come up with this. If this is correct it explains the blown primer.
Only thought on this would be to load some of the lower amounts and see if it conforms to the numbers and speeds here. Definitely start low as I'm not convinced this is the only issue.

Cartridge          : 7 mm Rem. Mag.(SAAMI)
Bullet             : .284, 160, Nosler AccuBond 54932
Useable Case Capaci: 72.286 grain H2O = 4.693 cm³
Cartridge O.A.L. L6: 3.290 inch = 83.57 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon H1000 ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.807% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-08.1   86    57.00   2798    2781   51460  10654    100.0    1.292
-07.3   87    57.50   2818    2822   52807  10703    100.0    1.277  ! Near Maximum !
-06.5   88    58.01   2839    2863   54187  10752    100.0    1.262  ! Near Maximum !
-05.7   89    58.51   2860    2905   55601  10800    100.0    1.248  ! Near Maximum !
-04.8   90    59.01   2880    2947   57050  10848    100.0    1.234  ! Near Maximum !
-04.0   90    59.51   2900    2989   58536  10896    100.0    1.219  ! Near Maximum !
-03.2   91    60.01   2921    3031   60058  10943    100.0    1.206  ! Near Maximum !
-02.4   92    60.51   2941    3073   61618  10989    100.0    1.192  !DANGEROUS LOAD-DO NOT USE!
-01.6   93    61.01   2961    3115   63217  11035    100.0    1.178  !DANGEROUS LOAD-DO NOT USE!
-00.8   93    61.51   2981    3157   64856  11080    100.0    1.165  !DANGEROUS LOAD-DO NOT USE!
+00.0   94    62.01   3001    3200   66537  11125    100.0    1.152  !DANGEROUS LOAD-DO NOT USE!
+00.8   95    62.51   3021    3243   68260  11169    100.0    1.139  !DANGEROUS LOAD-DO NOT USE!
+01.6   96    63.01   3041    3286   70027  11212    100.0    1.127  !DANGEROUS LOAD-DO NOT USE!
+02.4   96    63.51   3061    3329   71840  11255    100.0    1.114  !DANGEROUS LOAD-DO NOT USE!
+03.2   97    64.01   3081    3372   73699  11298    100.0    1.102  !DANGEROUS LOAD-DO NOT USE!
+04.0   98    64.51   3101    3416   75606  11340    100.0    1.090  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba     94    62.01   3045    3293   72860  10946    100.0    1.112  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     94    62.01   2948    3087   60177  11340    100.0    1.199  ! Near Maximum !

 

[C.Smith]

OK.
If 62 gr hit 3000 then here is what it looks like adjusting QuickLoad to fit that info. FWIW, I kind of think it may be something else also as I had to really manipulate burn rates and stuff to come up with this. If this is correct it explains the blown primer.
Only thought on this would be to load some of the lower amounts and see if it conforms to the numbers and speeds here. Definitely start low as I'm not convinced this is the only issue.

Cartridge          : 7 mm Rem. Mag.(SAAMI)
Bullet             : .284, 160, Nosler AccuBond 54932
Useable Case Capaci: 72.286 grain H2O = 4.693 cm³
Cartridge O.A.L. L6: 3.290 inch = 83.57 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon H1000 ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.807% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-08.1   86    57.00   2798    2781   51460  10654    100.0    1.292
-07.3   87    57.50   2818    2822   52807  10703    100.0    1.277  ! Near Maximum !
-06.5   88    58.01   2839    2863   54187  10752    100.0    1.262  ! Near Maximum !
-05.7   89    58.51   2860    2905   55601  10800    100.0    1.248  ! Near Maximum !
-04.8   90    59.01   2880    2947   57050  10848    100.0    1.234  ! Near Maximum !
-04.0   90    59.51   2900    2989   58536  10896    100.0    1.219  ! Near Maximum !
-03.2   91    60.01   2921    3031   60058  10943    100.0    1.206  ! Near Maximum !
-02.4   92    60.51   2941    3073   61618  10989    100.0    1.192  !DANGEROUS LOAD-DO NOT USE!
-01.6   93    61.01   2961    3115   63217  11035    100.0    1.178  !DANGEROUS LOAD-DO NOT USE!
-00.8   93    61.51   2981    3157   64856  11080    100.0    1.165  !DANGEROUS LOAD-DO NOT USE!
+00.0   94    62.01   3001    3200   66537  11125    100.0    1.152  !DANGEROUS LOAD-DO NOT USE!
+00.8   95    62.51   3021    3243   68260  11169    100.0    1.139  !DANGEROUS LOAD-DO NOT USE!
+01.6   96    63.01   3041    3286   70027  11212    100.0    1.127  !DANGEROUS LOAD-DO NOT USE!
+02.4   96    63.51   3061    3329   71840  11255    100.0    1.114  !DANGEROUS LOAD-DO NOT USE!
+03.2   97    64.01   3081    3372   73699  11298    100.0    1.102  !DANGEROUS LOAD-DO NOT USE!
+04.0   98    64.51   3101    3416   75606  11340    100.0    1.090  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba     94    62.01   3045    3293   72860  10946    100.0    1.112  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     94    62.01   2948    3087   60177  11340    100.0    1.199  ! Near Maximum !

Why would the reloading data be that far off? I had the same issue with RL 22 but loaded it in my son's 30-06 with no issues what so ever. I appreciate what you worked up here, I guess I'm having a hard time wrapping my head around it right now. I was really hoping to get 3000 fps or at least high 2900s where I had a safe load before.

Corey

 

[Polaris]

A thought mentioned above, not yet addressed, thinking it may be a strong possibility. Check and calibrate your scale. Also try weighing charges or a few different items (spare change, screws, nuts, bolts covering a useful range) in a few different physical locations and see if you are getting any deflections.

I'm convinced my house is haunted. A digital scale weighs the same powder charge, nominally in the 45 grain range, +/- 1.5 grains depending on which room I use it in. Granted, it's a cheap scale I use mostly for checking shotgun charge weights and calibrating bushings, but still rather unsettling phenomena.

As you've now had this issue with 2 different powders, not likely a lot issue. It is possible your particular system (components+rifle+conditions) do not work well together. I have seen this. Inexplicably "hot" loads in one rifle that show no signs in another.

After looking into the possibility of scale deflection, I would try a control load. I don't load 7RM, so I'd leave it up to a consensus of those who do, but something with a basic cup and core bullet and an old-time powder like IMR 4831.

 

[BF375]

How many rounds through this barrel? You may need a new tube.

 

[steve4102]

So was using brand new Hornady brass, with 160 accubonds, GM215M primers, and H1000. The load was 62 grains which hit 3000 fps which should have been 2800 fps. I got my hands on factory rounds and they shot fine. So i'm completely lost to what is going on. Barrel was clean no oil in it that i could see. Any ideas would help.

Corey

62gr is one grain Below Minimum according to Hodgdon.

http://www.hodgdonreloading.com/data/rifle

62gr should be roughly 2700fps out of a 24 inch barrel.

How far off the lands are seating these bullets?

did you weigh the bullets?

 

[JD338]

FWIW, I am loading my daughter's BF 7mm Rem Mag with the 160 gr AB and 63.0 grs RL22 with no issues and great accuracy out to 400 yds.

JD338

 

[OU812]

RL-22 is an excellent powder in a 7mm rem mag, that being said lot to lot variation can be quite a bit. Any time you change lot numbers of the same powder you need to back off your accuracy charge and work back up until you hit the same accuracy/speed.

With retumbo my 300 rum was .5 grains less in charge weight between to different lot numbers to achieve the same speed and accuracy.

With everything else being equal and the lot number change of RL-22 I would bet once you back down a few grains and work up you will find your accuracy once again and I am guessing it will be a lower charge than before.

 

[C.Smith]

A thought mentioned above, not yet addressed, thinking it may be a strong possibility. Check and calibrate your scale. Also try weighing charges or a few different items (spare change, screws, nuts, bolts covering a useful range) in a few different physical locations and see if you are getting any deflections.

I'm convinced my house is haunted. A digital scale weighs the same powder charge, nominally in the 45 grain range, +/- 1.5 grains depending on which room I use it in. Granted, it's a cheap scale I use mostly for checking shotgun charge weights and calibrating bushings, but still rather unsettling phenomena.

As you've now had this issue with 2 different powders, not likely a lot issue. It is possible your particular system (components+rifle+conditions) do not work well together. I have seen this. Inexplicably "hot" loads in one rifle that show no signs in another.

After looking into the possibility of scale deflection, I would try a control load. I don't load 7RM, so I'd leave it up to a consensus of those who do, but something with a basic cup and core bullet and an old-time powder like IMR 4831.

I started to test the scale thats a good idea thanks.

Corey

 

[C.Smith]

How many rounds through this barrel? You may need a new tube.

I probably have 500 rounds through the barrel. I would not think enough to burn it out.

Corey

 

[C.Smith]

So was using brand new Hornady brass, with 160 accubonds, GM215M primers, and H1000. The load was 62 grains which hit 3000 fps which should have been 2800 fps. I got my hands on factory rounds and they shot fine. So i'm completely lost to what is going on. Barrel was clean no oil in it that i could see. Any ideas would help.

Corey

62gr is one grain Below Minimum according to Hodgdon.

http://www.hodgdonreloading.com/data/rifle

62gr should be roughly 2700fps out of a 24 inch barrel.

How far off the lands are seating these bullets?

did you weigh the bullets?

Yes on the weight of the bullets. I did not weigh all of them but a few of them and measured them as well and they seem fine. I'm not sure how far of the lands I am now. Ioaded to an oal of 3.725.

Corey

 

[C.Smith]

RL-22 is an excellent powder in a 7mm rem mag, that being said lot to lot variation can be quite a bit. Any time you change lot numbers of the same powder you need to back off your accuracy charge and work back up until you hit the same accuracy/speed.

With retumbo my 300 rum was .5 grains less in charge weight between to different lot numbers to achieve the same speed and accuracy.

With everything else being equal and the lot number change of RL-22 I would bet once you back down a few grains and work up you will find your accuracy once again and I am guessing it will be a lower charge than before.

Thats what I did when I got new lots of RL 22, in fact bought four pounds of the same lot (all they had). I dropped down to the Nosler min and started seeing issues right away. Thats why I thought it was the powder and switched powders, but had the same issues.

Corey

 

[C.Smith]

And I'm not new to reloading, I've been loading for 18 years now and this is the first real issue I have ever had. So that's why the confusion for me. Well outside my knowledge range.

Corey

 

[ksubuck]

I have a few thoughts.

1. Carbon ring in chamber neck? Other fouling in chamber or throat? What is the brass thickness in the neck of the new brass? What is the neck diameter of a loaded round? Might be falsely increasing neck tension.
2. Scale accuracy? I check mine with a variety of different weight bullets, who needs calibration weights?
3. Bullet diameter? Are they fat?
4. Do factory loads have similar problem?
5. Does a mild load of the powder over-perform in a different rifle?

Good luck and be safe while figuring this one out!

 

[big rifle man]

This is going to sound crazy but if you are using Florescent lights check the scale both near and further away. A while back I read an article regarding how certain lighting elements can change things. Most likely a shot in the dark but give it a try.

 

[truck driver]

Not being smart but I would get a good beam scale and weigh one load at a time electronics are nice but I don't trust them I guess I'm just too old school.