Bullet Question?

[Casey Napier]

I have a couple questiones for the experts!

1) What is the difference between the Combined Tech 140Gr. Ballistic Silver tip, and a 140Gr. Nosler Ballistic Tip. I thought that they were the same bullet, just the CT BST was coated, but I measured a couple bullets today and noticed that the ogave on the CT BST was approx. .020 different than my Moly Coated BT's.

2) I am developing a load for my custom 7MM UM. I am using one of the bullets mentioned above (140Gr) and 70Gr's of 7828. This combo gives under 1/2" groups with no pressure sighns, but it is 1 grain above max in the load manual that I have. Do yall think I will be okay?

3) Why does my neck sized brass stick slightly in the chamber, on the rear stroke of my bolt (no bolt lock up, the handle lifts fine)? This is the first time I have neck sized only my brass so I was wondering if this was normal? And yes they were previously fired in the same gun, no resistance when I chamber a round.

4) What about opinions on the above bullets for long range whitetail deer? Minimum shot distance will be 200 yards, max will be approx 500 yards. Bullet is moving 3500 @ 10 feet from muzzle. Thought I might try some Accubonds, but as I mentioned in a recent post, wouldn't the BT perform better at the distances I mentioned above because the velocity should be under 3000 @ 200 yards?

Thanks
RidgeRooster

 

[Fiftydriver]

1. Its not coated but it has been treated on the surface with a chemical that oxidizes the jacket to make it black in appearance. It is said this helps harden the jacket surface to reduce bore friction, I have not see that this works or reduces bore fouling over a standard BT but it may.

2. Your case life will tell you if your running to much pressure. Is this a 7mm Rem Mag of 7mm Ultra Mag? I assume its a Rem Mag if your using 70 grains of powder but you listed your round as a 7mm UM????

Watch for normal pressure signs such as increased effort to lift bolt, overly flattened primers, possible firing pin cratering on primer or extractor marks on case heads after firing. Any one of these by itself is not really a true indicator that your pressures are to high but it could be.

3. In any high performance magnum round, it is not really smart to only neck size with top end loads. The reason is because once you get into magnum sized rounds, there is enough surface area on the case to grip the chamber very tightly. If you do not reduce the size of the case after firing you will get stick extraction.

I recommend partial FL sizing of the case, just enough so that you size as much of the case as possible without bumping the shoulder position on the case. Just to be sure, its best to check your sized cases by chambering them in your rifle before loading the case up. It should chamber easily with at the most a very slight resistance when you close the bolt, just enough to be able to tell there is a case in the chamber is all you want. If the bolt is harder to close then this, you need to size your cases more.

If your sized cases chamber easily, then its either a rough chamber issue or your running higher pressures then you should be.

4. That bullet will work great out to 500 yards on any whitetail. 3500 fps, we really need to know what chambering your shooting. If its a Rem Mag, your pushing things hard if your getting this velocity in a standard length barrel. If your using the RUM then your about right with very top end loads but the powder charge seems light to me.

If your running the RUM, there are much better powders out there for you to use such as Rl-25, H-1000 and Retumbo.

The 140 gr Accubond would in my opinion be a much better bullet then either the Ballistic Tip or Ballistic Silvertip. It will open up just as easily at long range, have the same BC, generally shoots identically to the other bullets but has the bonded core for higher weight retention for closer range shots or impacts on heavy bone.

Again, In my opinion, there is no comparision between the Accubond and the others, the Accubond is a far better choice.

Kirby Allen(50)

 

[Casey Napier]

Thanks for the info! My charge is 90Gr. 7828 in a 7MM UM Max is 89 according to the load manual I have, sorry for the confusion.

I could not get very good results with R25 or Retumbo, I will try some 1000.

Will non Molyed bullets increase pressure if I deside to switch to Accubonds? I guess what I am asking is should I start a little lower in grains and work up. I have been shooting Moly coated BT's.

How about opinions of Moly!

RidgeRooster

 

[remingtonman_25_06]

I'd definately think about the AB's like Fifty mentioned... 3500fps is pretty fast for NBT, but like you said, 200 yard minimum, the velocity will be what (xxxx) but under 3000fps I imagine...If you put the NBT behind the shoudler you wont ahve any problems..At longer range, you should be able to punch through shoulders because the lower velcoity will allow the bullet to penetrate..

I always thought the NBT's, and the Win CTBST's were the smae except the coating myself...I've only shot the .257" version 85, and 115g. I did not note any better accuracy, but did pick up 100-150fps. I did not notice any easier cleaning as it was a RUger factory barrel, so that pretty much sums that up...It was not any worse though..

 

[Casey Napier]

I used my bullet comparitor to measure the bullets, and to my suprise they measured different .020 approx. The box of BT's were a couple of years old, and the CT BST were new. Maybe they made a change?

RidgeRooster

 

[Fiftydriver]

Molied bullets will drop pressures. Also, if you develope a load using moly coated bullets and switch to non coated bullets without dropping your powder charge, the pressures will increase.

The Ballistic Silvertips are not moly coated however. Still, it would be wise to drop back to the starting load and work up again when switching any bullet.

With the different powders, use what shoots best, the IMR powder can just be a bit finicky with temp changes in my experience but other then that it shoots well.

The difference your seeing in your bullets is more then likely just lot to lot variations expecially of some of your bullets are older. This is not uncommon to see this much lot to lot variation from even the big bullet makers.

Have you ever considered shooting the 160 gr Accubond? I have found the heavier bullets make these big cases shoot much more consistantly. The 7mm RUM will get you around 3300 fps with the 160 gr pill.

Kirby Allen(50)

 

[Casey Napier]

Sounds like I may need to give them a try! I have noticed that this particular gun is a little bit inconsistant. I have been experimenting all morning with 120 TSX, 140 AB, 140 CTBST, and 150 Speer Schricco's. Did not play around with powders because my local dealer was out of H 1000. I am getting the best groups with the 140 BT Moly and the CTBST's, I might punch a .250 group, and then turn around and shoot a .75 with the same load. I know the gun is put together well, Brad Stair (Performance Guns) out of Utah built this rifle.

I will pick up a box of 160 AB if they have any at the local Sporting Goods store, and expirement with them. Do you have any suggestions on which powder you have had the best luck with? I assume H 1000 and R-25 in which you mentioned above?

Thanks and excuse my spelling!
RidgeRooster

 

[davewilson]

i used the 180 Berger's in my 7rum. as Kirby said, these big over-bores will just shoot the heavier bullets more consistently. they also have a 168. they'll work great on whitetails. you didn't mention your twist rate.is it less than 10?

 

[Casey Napier]

To be honest, I can not remember! I will check, but I remember telling my Smith that I was planning on shooting 140's. I had this rifle built with the intentions of using it for Kentucky long range, 200 to 500 yards, and was planning on using the lighter bullets to keep my trajectory pretty flat, that way I could compinsate a hold over. I used this rifle in the factory configuration prior to having it accurized, and killed several deer around the 400 mark. I know the range, click, and shoot method is a more accurate method, but where I hunt I just barely have time to range and shoot. I usually range terrain features so if the deer is moving fast and I do not have enough time to range, I can still pretty accuratly guess yardage, more of a reason to flatten trajectory. If I were going to go any further than 500, I would deffinetly use the click method. I thought about trying one of the Kenton Industries dial. What do yall think of them?

I will give the 160 AB's a try and see if it makes my gun a little more consistant.

Thanks and excuse my spelling!
RidgeRooster

 

[Fiftydriver]

Dave brings up another point and looking at the list of bullets you are testing, they all have one thing in common, they are all relatively hard bullets.

Now some of you will read that and think the youngster from Montana has lost his marbles if he things an Accubond and Ballistic Tip are hard bullets.

Well, in fact they are, at least in the area that I am concerned with, the base. They have very heavy, thick, solid guilding metal bases which are even harder then all copper bullet bases such as the Barnes and Swift.

As such, all the bullets you are testing will not easily bump up under pressure to fill your bore diameter.

You may well see an improvement in consistancy going with a more conventional cup jacketed bullet design such as a Hornady A-Max or SST or a Sierra MK or Gameking or a Wildcat Bullet custom bullet such as the 175 gr ULD RBBT. The Bergers as mentioned are also a great bullet to try as well.

Generally these all will shoot very well because their thin jackets and pure lead cores will allow the base of the bullet to easily and consistantly bump up under pressure to fill the bore and you will in most cases get more consistant shot to shot performance.

There is a reason all popular BR match bullets are cup jacketed bullets. There is also a reason that long range solid match bullets are critically dependant on bore diameter to shoot well.

You may want to try some softer bullets. Any of the one mentioned above will be more then enough for any deer and in most cases elk as well.

Kirby Allen(50)

 

[Casey Napier]

Thanks for the information and advice. I have really learned alot since I started browsing this site and really value yalls opinions!

I was sitting at my loading bench this evening and noticed I had a pound of AA8700. Anyway I was bored and wanted to do some shooting(My local sporting goods store did not have any 7MM 160 AB's that I wanted to try), so I started looking through my load manuals and decided to see what I could do with the 120 TSX's and the old AA8700 that has been gathering dust for a couple of years. AA8700 is the quickest powder for a 130Gr. bullet in my Lyman load manual, it did not show a load for a 120. To my suprise, 110Gr's of AA8700 (which is the max load reccomended for the 130) and the 120 7MM TSX produced a consistant 1/2" or better group once I found the sweet spot seating depth. I even shot a .526 5-shot group. I have no idea how fast these little bullets are flying but I would guess around 3600+ out of my Ulti-Mag.
How about this combo for a deer round out to 500 yards?

Opinions wanted!

I am scared I am going to shoot the riflings out of my Ulti-Mag but dang its fun!!!

Thanks

RidgeRooster