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 Post subject: Problem with grouping
PostPosted: Thu Apr 06, 2017 1:45 pm 

Joined: Mon Apr 03, 2017 9:15 pm
Posts: 1
I don't have a chrono, and here are some results. I shoot Howa 308 Bull barrel. Loaded Norma cases with 42.2gr S335 Somchem powder, inserted PMP primer with 155gr Nosler Custom Competition.

I would like to know if there is a way to better my grouping without the use of a Chronograph
Shot @ 100m.
Optic: Burris Eliminator 3ImageImageImageImage

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 Post subject: Re: Problem with grouping
PostPosted: Thu Apr 06, 2017 2:20 pm 

Joined: Wed Nov 08, 2006 2:49 pm
Posts: 32179
Location: Northern British Columbia
Welcome aboard. Always glad to see new people posting. First off, the second group displayed is not bad. It shows some promise. Perhaps you just need to play with seating depth. With cup-and-core bullets, such as the Nosler CC, I find that seating as near the lands as possible yields the best accuracy. This assumes that you are able to fit the case into the magazine or that you are comfortable single loading if the style of shooting is punching paper. Do you know how far off the lands you are seating the bullets?

A rough estimate using QL suggests that you have room to increase velocity, which often increases accuracy as you approximate maximum pressure. The following is using CIP standards for the .308.

Code:
Cartridge          : .308 Win. (CIP)
Bullet             : .308, 155, Nosler CC HPBT J4 53155
Useable Case Capaci: 49.870 grain H2O = 3.238 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 22.0 inch = 558.8 mm
Powder             : Somchem S335

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0   80    36.00   2253    1748   32136   6340     96.8    1.393
-18.0   82    36.90   2304    1826   34180   6491     97.5    1.360
-16.0   84    37.80   2353    1906   36347   6635     98.1    1.327
-14.0   86    38.70   2403    1987   38642   6770     98.7    1.293
-12.0   88    39.60   2452    2069   41075   6896     99.1    1.256
-10.0   90    40.50   2500    2152   43654   7012     99.4    1.221
-08.0   92    41.40   2549    2236   46388   7118     99.7    1.188
-06.0   94    42.30   2597    2320   49289   7213     99.9    1.156
-04.0   96    43.20   2644    2406   52368   7298    100.0    1.125  ! Near Maximum !
-02.0   98    44.10   2691    2492   55636   7372    100.0    1.095  ! Near Maximum !
+00.0  100    45.00   2737    2579   59110   7442    100.0    1.066  ! Near Maximum !
+02.0  102    45.90   2783    2666   62803   7510    100.0    1.039  !DANGEROUS LOAD-DO NOT USE!
+04.0  104    46.80   2829    2754   66733   7576    100.0    1.012  !DANGEROUS LOAD-DO NOT USE!
+06.0  106    47.70   2874    2843   70920   7640    100.0    0.987  !DANGEROUS LOAD-DO NOT USE!
+08.0  108    48.60   2919    2933   75384   7702    100.0    0.962  !DANGEROUS LOAD-DO NOT USE!
+10.0  110    49.50   2964    3024   80148   7761    100.0    0.938  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba    100    45.00   2819    2735   69298   7177    100.0    1.001  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    100    45.00   2614    2351   48997   7648     98.5    1.155


SAAMI standards will increase velocity and maximum chamber pressure slightly. The point is that you actually have some room to attempt to increase powder charge.

There is always the option of testing another power, if such is available to you. Some suggestions include:

Code:
Cartridge          : .308 Win. (CIP)
Bullet             : .308, 155, Nosler CC HPBT J4 53155
Useable Case Capaci: 49.865 grain H2O = 3.238 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 22.0 inch = 558.8 mm

Predicted Data for Indicated Charges of the Following Powders.
Matching Maximum Pressure: 59450 psi, or 409 MPa
or a maximum loading ratio or filling of 110 %
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
ReloadSwiss RS 60                  110.0     53.0     3.44    2953    99.6    59450    9826   1.014  ! Near Maximum !
Elcho 17                           109.2     52.6     3.41    2938    98.9    59450    9688   1.017  ! Near Maximum !
Alliant Reloder-17                 109.2     52.6     3.41    2938    98.9    59450    9688   1.017  ! Near Maximum !
Winchester 760                     108.2     52.6     3.41    2879    94.2    59450    9387   1.029  ! Near Maximum !
Hodgdon H414                       108.2     52.6     3.41    2879    94.2    59450    9387   1.029  ! Near Maximum !
PB Clermont PCL 511                110.0     53.9     3.49    2866    94.9    58234    9418   1.036  ! Near Maximum !
Vihtavuori N550                    110.0     51.7     3.35    2861    96.8    57486    9339   1.049  ! Near Maximum !
Bofors RP3                         106.0     49.3     3.19    2857    99.2    59450    8841   1.051  ! Near Maximum !
Norma 203 old                      106.0     49.3     3.19    2857    99.2    59450    8841   1.051  ! Near Maximum !
Rottweil R903                      108.4     49.3     3.19    2848    99.0    59450    8746   1.051  ! Near Maximum !
Accurate 4064                      106.3     47.8     3.10    2844   100.0    59450    8369   1.070  ! Near Maximum !
Somchem S355                       108.0     48.6     3.15    2837    98.9    59450    8711   1.050  ! Near Maximum !
Accurate 2520                       98.4     47.7     3.09    2837   100.0    59450    8354   1.054  ! Near Maximum !
Lovex D073.6                       100.7     47.7     3.09    2837   100.0    59450    8354   1.054  ! Near Maximum !
Hodgdon H380                       104.7     49.2     3.19    2832    96.8    59450    8868   1.048  ! Near Maximum !
Accurate 2495                      100.2     45.1     2.92    2829   100.0    59450    8021   1.076  ! Near Maximum !
SNPE Vectan SP 7                    98.7     48.7     3.15    2800    96.7    59450    8524   1.054  ! Near Maximum !
ReloadSwiss RS 62                  110.0     53.0     3.43    2798    95.4    51807    9289   1.090  ! Near Maximum !
Lovex D073.5                        94.0     46.4     3.00    2794    99.8    59450    8107   1.064  ! Near Maximum !
Accurate 2460                       93.7     46.4     3.00    2794    99.8    59450    8107   1.064  ! Near Maximum !
Rottweil R901                       99.1     43.3     2.80    2785   100.0    59450    7960   1.071  ! Near Maximum !
Bofors RP7                         109.2     49.3     3.19    2779    93.3    59450    8565   1.053  ! Near Maximum !
Rottweil R907                      109.2     49.3     3.19    2779    93.3    59450    8565   1.053  ! Near Maximum !
IMR 4007 SSC                       105.8     49.3     3.20    2778    93.3    59450    8558   1.053  ! Near Maximum !
Accurate 4350                      110.0     50.6     3.28    2772    95.8    51221    9054   1.107  ! Near Maximum !
Lovex S065                         110.0     49.5     3.21    2770    95.4    57362    8569   1.070  ! Near Maximum !
Norma URP                          110.0     50.0     3.24    2769    95.7    51653    8998   1.094  ! Near Maximum !
Bofors RP19 ~approximation         110.0     50.0     3.24    2768    95.7    51602    8992   1.095  ! Near Maximum !
Norma 204                          110.0     52.2     3.38    2760    89.9    55346    8828   1.065  ! Near Maximum !
Ramshot Hunter                     110.0     52.2     3.38    2759    93.2    51706    9092   1.093  ! Near Maximum !
Lovex S070                         110.0     50.0     3.24    2741    93.3    54391    8660   1.093  ! Near Maximum !

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 Post subject: Re: Problem with grouping
PostPosted: Thu Apr 06, 2017 3:33 pm 

Joined: Thu Apr 06, 2006 8:42 am
Posts: 14377
Location: Washington State
I'd just add that a chronograph is absolutely NOT needed to develop accurate loads. Many excellent loads were achieved long before the advent of affordable chronographs.

They are good tools though, for any handloader.

That 155 gr bullet is a very good performer in the .308 Winchester, and your groups do show promise!

Welcome Aboard! Guy


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 Post subject: Re: Problem with grouping
PostPosted: Thu Apr 06, 2017 3:41 pm 

Joined: Sat Feb 13, 2016 10:16 am
Posts: 1234
A chronograph is not really needed to find a load for your rifle, but I prefer it to check ES / SD and speed. You can check your manuals and select a load in between min and max, work up with 3 round groups in .4 increments up to max. I would say that H4895, Varget and IMR 4064 are great powders for the .308

You can try to use your powder, just work up and watch pressure. See below on my work ups across the paper with Varget and IMR 4064 until I found a node for both. Good luck.

Image

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 Post subject: Re: Problem with grouping
PostPosted: Fri Apr 07, 2017 7:13 am 
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Joined: Sun Oct 09, 2016 9:56 am
Posts: 99
Location: South Carolina
I believe your brass is OK but I would use components that were known to be accurate in the .308. The 2 powders you should be working with are H-4895 and Varget. The primers I've had good luck with are Fed 210 and WLR. I don't see any difference on paper in GM210M and the 210 But use the primer that fits your case best. You need to be able to feel your primer seat and seat them all the same. I haven't found Nosler 155 or 168 Competition bullets to be very accurate in some rifles and found the Nosler BT to be more accurate. So you may want to try some. I would seat your bullets .010" or less from the lands and forget about seating depth unless they won't fit your mag. I would start with a charge in the middle of starting load to max, load 10 rounds, go to the range and fire two 5 shot groups. Record the measured groups, increase the powder charge 1 grain and do the same thing over again till the accuracy falls off or you reach max charge. When you hit on a good load seating depth won't make much difference and 1 grain in powder charge won't either. It takes a bit of trial and era to find what your rifle likes .
Billy


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