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Need Loading Help

12 Dec 2018
@ 09:22 am (GMT)

Austin Nelson

Just getting into rifles and reloading. Doing it all through the information on Nathan's books. I believe all is going fairly well but I am not sure how to proceed from the point I'm at.

Rifle is a Tikka T3 7mm RM. Bullets are 162 ELD-x and powder is H1000. I have been working up initial loads and trying to find high pressure signs (which I have not found). Book Max is 68.5 gr for this round and I have gone up to 72 grains without pressure signs thus far (not really sure if I should push it farther).

I have some groups which are pretty tight and some groups with very low ES, but no groups with both characteristics.

Load Results as follows:
66 gr
.331 group
ES 29
SD 14.7
Avg 2801fps

66.5 gr
.793 group
ES 17
SD 12.1
Avg 2780 fps

67 gr
1.6" group
ES 28
SD 18.8
Avg 2820 fps

67.5 gr
1.23" group
ES 40
SD 28.6
Avg 2862 fps

68 gr
1.21 group
ES 43
SD 22.8
Avg 2869 fps

68.5 gr
.683" group
ES 20
SD 10.5
Avg 2918fps

69 gr
1.29" group
ES 20
SD 10.8
Avg 2918 fps

69.5 gr
.852" group
ES 18
SD 8.8
Avg 2954 fps

70 gr
.985" group
ES 13
SD 6.7
Avg 2966 fps

70.5 gr
.92" group
ES 6
SD 4.3
Avg 2956 fps

71 gr
1.03 group
ES 29
SD 14.6
Avg 2986 fps

71.5 gr
1.6" group
ES 4
SD 3
Avg 3037 fps

72 gr
1.48" group
ES 34
SD 16.8
Avg 3030 fps

Any advice on how to proceed from this point would be greatly appreciated.
Thanks

Replies

12 Dec 2018
@ 02:09 pm (GMT)

Chris Murphy

Re: Need Loading Help
Hi Austin with the info you have put forward id say it is not so much your loading but a ridiculously light magnum issue. if you note the higher the load and the faster you got the bigger your groups 70-70.5grain could possibly be tighter but what is against you is recoil from a light weight magnum verses new shooter and un refined skills. the other thing i would suggest is going the the 162 ELD-M the x bullet can give odd pressure spikes and flyers due to its thicker jacket.
73-74 grains is usually the upper limit for the 7mm and 162 ELD-M be very cautious going higher than you have with the X bullet
12 Dec 2018
@ 03:20 pm (GMT)

Austin Nelson

Re: Need Loading Help
Appreciate the reply, I should also add that bullets are loaded 10 thousand off the lands, and I do have a brake on the rifle.
Thanks
13 Dec 2018
@ 03:36 am (GMT)

Paul Leverman

Re: Need Loading Help
From the figures posted, I would go back to the first load and do some experimenting with crimping and seating depths.
13 Dec 2018
@ 08:41 am (GMT)

Nathan Foster

Re: Need Loading Help
OK, here we go. Expert advice, otherwise known as long distance guess work.

Human issues.

1. There is a high possibility that the brake is reducing recoil to the shoulder but then creating a concussion shock wave which creates a more subtle yet insidious problem. This problem can be worse than issues caused by felt recoil. Not a great many people understand this so don't bother googling it.

2. Brake is removed to isolate rifle on its own but technique is not optimal to control rifle. If so, this should be seen as a core issue. Fix this issue via technique, not via alterations to the rifle during formative learning. Alter the rifle following personal mastery. A bit like saying- well I know the rifle has potential, groups are looking good, but now the testing is done, I can see its still too light for me to use with a fast heart rate on a windy ridge so now I will set about obtaining a fatter stock etc. This order of steps is quite important for long term success in this field because you have isolated the most important variable, yourself.

Gun issues.

1. Brake is is not venting correctly. Remove brake to isolate this variable.
2. Loads are not concentric, yaw increased with additional velocity / spin. Study bullet run out (Sinclair gauge) to assess this.
3. Action screws over torqued (see Accurizing book / Tikka set up video).
4. (now or later) Muzzle gradually swells at threads. Too narrow for this power level over time.
5. Carbon caking at muzzle section makes already slippery bore too slippery. Also possible carbon caking further back towards chamber depending on brake design. Look for obvious signs of heavy carbon during extraction, smoke coming from chamber.

Velocity wise, your rifle is producing the same speed as Hornady SF ammo. The Tikka rifles often shoot well with this load. But again, other variables have to be isolated.
15 Dec 2018
@ 07:47 am (GMT)

Nathan Foster

Re: Need Loading Help
One more to add to this (hopefully does not apply to the above rifle), keeps catching me out when guys neglect to mention the exact specs of their rifles to me. If you have a Fluted T3 Lite (or Sako) and its not shooting straight, the barrel has to be pulled. The fluted models swell at the flutes over a period time and depending on the power level. Evidence can be obtained via slugging the barrel. No further advice can be offered for these models.
15 Dec 2018
@ 11:46 am (GMT)

Iain

Re: Need Loading Help
If you know someone whose experience and ability with light, powerful rifles you have confidence in; have them shoot the 70 and the 70.5 gn loads and see what size groups they can achieve.

Might be best to do this after at least some of the rifle checks suggested have been carried out. Or maybe before the checks and again afterwards . Then you will have a better idea of what is causing what.
16 Dec 2018
@ 04:34 am (GMT)

Austin Nelson

Re: Need Loading Help
Thanks for the replies, and also please forgive the tardy response. I had eye surgery this week and reading and what not is a bit taxing.

As a response to the listed possible issues,

1) I will try removing the brake, and see how that goes. Not sure what to look for here though? Am I to redo load development? How will this affect the rifle when the brake is added back?

2) I have checked my rounds with the concentricity gauge, and they are within the specs Nathan listed as "good" in the reloading book.

3) Action screws are torqued to spec

4) As regards to possible future muzzle swelling, I am not sure what to do about this at this point?

5) Heavy carbon does not seem to be an issue

6) The barrel is not fluted

7) I really do not know anyone who could test this for me...

All the help is greatly appreciated !
16 Dec 2018
@ 04:38 am (GMT)

Austin Nelson

Re: Need Loading Help
As far as exact rifle specs:
Tikka T3X 7mm rem mag
Bedded per Nathans videos
Mountain Tactical bottom metal
JP Recoil Eliminator brake

Ammunition:
Win Brass
162 grain ELD X
H1000 Powder
CCI 250 Primer
16 Dec 2018
@ 09:20 am (GMT)

Nathan Foster

Re: Need Loading Help
Ok, some useful info in that reply.

Yes, brake off please. Especially this design. Test the rifle without the brake. If it shoots well, I want you to go find someone who can dock and clean up the muzzle afterwards to prevent muzzle swelling issues later on.

For now, clean the barrel again, get it back to bare steel with solvent, spiral the chamber, using a bronze brush and harsh solvent, soak, scrub, soak, scrub then clean it all out and get the bore dry and ready for shooting.

Fire about 4 foulers. Use these to get your technique in check.

Then fire your groups, very slow, again, technique in check. I don't want to go over my shooting book details here but will say this- your fingers / knuckles should be white when shooting and sore when finished for the day, like a good honest hard days work. The rest you shoot over needs to have a good cradle shape to it and should be fairly soft. If you have tight sand bags, undo them and pour some sand out, needs to be fairly soft / cradled to suit this rig (also better emulates back packs).

Possibly start back at 70 and go through to 72 for this rifle. Just study behavior at this stage.

You'll need to take this step by step. Can't really go with any "what if its x variable" at this stage.

Guys- please trust me when I say that the thinner the barrel, the more careful we have to be. Threading the muzzle, fluting, all of these things can be highly problematic. I also need you to understand that some of the more funky brake designs can kill a barrel in just a few shots. Try to develop a mindset where you avoid add-ons unless you have no choice (which you cannot discover until after testing / load work). If for example you have a .375 cal rifle, consider optimizing the stock before adding a brake.
16 Dec 2018
@ 10:19 am (GMT)

Austin Nelson

Re: Need Loading Help
Thanks for the reply!

Is there any reason not to just go ahead and have the barrel docked at this point?
16 Dec 2018
@ 11:06 am (GMT)

Nathan Foster

Re: Need Loading Help
Yes, you could do this now Austin.

 

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