7.5 Swiss deer load.

[Exposure]

O.K. I know its early for deer season talk but I am starting load development early here!

I put together my first trial loads this morning and took them to the range. Results were marginal in the accuracy department so I am calling on the wealth of knowledge here at THR to point me in the right direction.

Rifle:

1953 Swiss K31 with St. Marie clamp on mount and Tasco 3-9X scope.

Load:

PRVI once fired cases
Nosler 165 grain ballistic tips
44.0 grains IMR 4064
CCI #200 LR primers
OAL of 3.010 inches

5 Shots fell into a 2.250 in circle at 100 yards. I was disappointed, my 168 grain SMK load will shoot 3/8" inch groups from this same rifle, but it moves much slower as it is a target only load.

Velocity was good. High of 2618 and low of 2565 for a spread of only 53 FPS. I am sure this is more than enough velocity to get the ballistic tip to open. Primers were slightly flattened but extraction was still very easy with no extra effort involved. I think there is a lot room left to get this round going faster.

But my real gripe is with the rather large 2.25" group. I am thinking it is the jump to the lands that is causing poor grouping. These are the first Nosler BT's I have ever fired from this rifle so I may try some changes in seating depth.

Any of you guys have some input? I can live with a 2" deer gun but I would much prefer it to be 1" or less.

As a side note, I shot a 1/2 gallon milk just full of water with one of these loads and the results were devastating. The jug was essentially vaporized, so as I said above I am sure the velocity I am getting is more than enough to open up the ballistic tip.

 

[PotatoJudge]

What is your SMK load? Have you tried that load with NBTs? You don't need a ton of velocity with the BT and at that weight and caliber you're not likely to have problems with performance.

 

[Exposure]

PotatoJudge-

The 168 SMK load is as follows:

PRVI fired cases
43.0 grains IMR 4064
168 SMK
CCI #200 LR primer
OAL of 2.940"

This yields a velocity in the 2400 FPS range. I was hoping to get considerably more than that with the Nosler BT's. In fact I was hoping for 2700+

When I made my first dummy round this morning I seated the Nosler BT at the same 2.940" OAL and it was obvious that it was going to be a big jump to the lands at that distance. Apparently the Ogive on the SMK is much further forward than the Nosler BT. So that is why I moved the OAL up to 3.010" I think it may need to be even further forward. I am also thinking perhaps another grain of powder to bring the charge to 45.0 grains. But I will change only thing at a time and see what happens.

I have heard that the Nosler BT's don't need a lot of velocity to open, like only 1800 FPS or so maybe? Not sure. But I would prefer to have the round moving as fast and as accurately as possible. Hopefully I can put those two things together!

Thanks for the help.

 

[PT1911]

I am confused as to why you are worrying about gaining speed from a round that is moving 2400 FPS and is capable of shooting good groups. I would stop and go hunting. People spend thousands of dollars on guns that will shoot that well.... and if I read correctly you are shooting deer..... the load you have developed for your gun is more than capable of dropping a deer in its tracks..... I dunno...perhaps I am missing something here.

 

[Exposure]

You are right PT1911-

Like many I am too caught up in the whole velocity thing. I just want max velocity with max accuracy. I should be more than happy with 2" at 100 yards and 2550 FPS avg.

I'm just a guy that likes to play around in the details, it's fun!

 

[PT1911]

well... at least you have a load to fall back on... nice to start out with a successful load... if you can get it faster and tighter... even better...

 

[PTK]

In Maine, you're not going to encounter a deer that won't drop like a rock with 165gr soft point/ballistic tip going anything faster than 1500FPS. In fact, faster speeds will simply make it get LESS penetration!

 

[Slamfire]

I tried AA4350, which provides the same velocity grain for grain as IMR 4350, in the 7.5 Swiss. It shot well at 100 yards with irons. Sub 2" groups, in a service rifle, with a post are just fine in my opinion.

I don't know why your bullet is not grouping, try something else.

[SIZE="3"]7.5 x 55 Swiss  Model K-31

168 gr Nosler Match  51.0 gr AA4350 INDEP brass and primer OAL 2.850		
22 Dec 01 T = 58 ° F								
Ave Vel =	2536					 		
Std Dev =	17					 		
ES =	45					 		
Low =	2510					 		
High =	2555					 		
N=	9							

about 2"								
								
168 gr Nosler Match  52.0 gr AA4350 INDEP brass and primer OAL 2.850		
22 Dec 01 T = 58 ° F								
Ave Vel =	2624				 	 		
Std Dev =	31				 	 		
ES =	72				 	 		
Low =	2588				 	 		
High =	2660				 	 		
N=5
1.5" * .75

AP11 Swiss Ball headstamp DA 78
		
Ave Vel =	2565	
Std Dev =	11	
ES =	23	
Low =	2551	
High =	2574	
N=4[/SIZE]