300 RUM Bullet Crimping

[cserwin]

I am new to reloading, and may be biting off a big chunk starting out with 300 RUM loads. Anybody have good advice on bullet crimping. Every factory load I've shot has had crimping, and would assume with the recoil it would be needed. I'll be loading TTSX, and would like to try VLD's as well. This is a topic I see almost nothing at all about.

I'd appreciate some expert advice on this, and anything else that may need to be considered. I'm looking to work up accurate loads for this rifle before hunting season. I just had a custom builder build this gun on a factory action. Blueprinted action, Lilja barrel, and McMillan stock, Timney trigger and want to squeeze all the accuracy potential from it after the money that I've spent with all the custom work.

I'd appreciate some advice

 

[Korhil78]

I would recommend against crimping your reloads in your 300 RUM. There is really no need to. I have never crimped any of my loads and don't even crimp my rounds in my AR type rifles. The recoil is not going to be bad enough to knock the bullet into the case much if at all even with a RUM. In my opinion, You will get better results w/o crimping.

If you have not ever reloaded, I would suggest buying the Barnes reloading manual that they have available. You should read all the information that it gives you on reloading in order to better educate yourself on the art of reloading. You can also find a lot of information on this website by doing a search.

With the barnes bullet, I have found that it likes a good jump to the lands. You can start with the recommended seating depth that the barnes manual gives you and then play with the seating depth after you find an accurate load (you will understand more about what I am talking about when you read the reloading manual).

 

[cserwin]

Thanks for the response. I have a Barnes manual, and will continue my research here, and elsewhere. I will give it a try, and see what happens, but like you said I still need to educate myself a little more.

I appreciate the advice!

 

[Korhil78]

No problem, if you have any other questions in the course of your reloading process, feel free to post it. I will try my best to answer your questions and there are a ton of people on here with more experience than I that can chime in too.

 

[bushwacker09]

hello fellow newbie reloader r u sure they r crimped or r seeing the canulure line on the bullet. havent figured out some bullets have the canulure some dont .maybe someone can chime in is there a advantage or not 2 have it.always thought that was a inspection line 4 factory ammo thanks jeff

 

[Lefty7mmstw]

Most factory ammo has at least some crimp because they have no idea at all how much hell you will put your ammo through before it is finally fired.
I've loaded thousands of rounds up to 375 h@h(8# rifle) and 405 win, and the only rounds that are crimped are the lever gun rounds, since the case mouth could snag on feeding. I used to crimp the 375, but I've tried without and it's fine.
A slight taper crimp to help with feeding issues is fine on AR rifles is fine, but most don't need it unless the bullet is a heavy match bullet. They sometimes have enough inertia to move a bullet as the action closes on it. I personally don't crimp AR ammo, even with 75 gr. bullets.
I do crimp bullets for my revolver also, same reason as the AR, bullets could move. The powder used in revolver rounds also requires a lot of "pull" for consistent ignition.

 

[cserwin]

Thanks for the replies. All the factory ammo by any manufacture I've bought has had a visible crimp, no cannelure. I do agree with Lefty 7mm, and it is probably a manufacturing guideline to crimp bullets of magnum rounds. I'll also be loading .45 acp, and .44 mag, so bullet crimping may be needed in those cases.
I spent time last night reading post's on 300 RUM, and apparently there have been problems with chamber dimensions associated (chambers too tight), and FL resizing not bringing case dimensions back to tolerance with the overly tight chambers. First loadings, and factory loadings fine but extraction, and pressure problems on each successive loading.
I've not gotten this gun back from the gun builder yet, but would expect to by the end of this month.
Any suggestion on case trimmers? I have an RCBS Trim Pro, and have been trimming new cases down .001 over specified trim to length .44 mag, 45 acp. The Trim Pro does not seem to be cutting very square even with pilot, and have had to adjust constantly to get consistent trim lengths. I wondered if the rough adjustment screw was just not holding as I was having to adjust after each case. In any event, with my brilliance in solving these type things I had the bright idea to put a split shot in each screw hole in hopes that it would grip a little better, and good luck ever getting the lead out of theadjustment screw holes without channelocks, and maybe damaging the threads. Thought about a little heat to loosen the lead up, but will probable do some thread damage in the process. I think in the end you get what you pay for. I'm considering the Wilson trimmer with cartridge specific case holders. Does anyone know if these case holders work equally well with new brass, as firedbrass? Is the Wilson worth the money?
Sorry so long a post

 

[cserwin]

Another question is in powder selection. This gun will be used for big game hunting in the Rockies. My load development will be done in 90-95 degree weather. My hunting will be done in much cooler temps, estimated 20-30 degrees. Which of the magnum powders are the most temperature stable? Not just magnum powders, as I'll be loading for 7mm-08 as well. What will my best options be in powder selection based on temp differentials?

I'm a beginner to reloading so all advice, and recommendations will be seriously considered, and appreciated

 

[Korhil78]

cserwin,

The Wilson trimmer is a very good one. I have it with the micrometer adjustment added on from Sinclair Int. they have te individual shell holders for unfired and fired cases for most calibers so you can just buy both shell holders for the 300 RUM and be good. I would also invest in a OAL gauge so that you can find out how far out you can seat a bullet before it touches the lands on your rifle.

The powder that you use is also fining to depend on what weight bullet you are going to use. When I was loading for the 300 RUM, I was getting good results with Retumbo and H1000 which both are temp stable powders. I was using a 210 gr Berger. I do believe that Barnes has a 200 gr bullet that work well for you.

 

[cserwin]

Thanks for the input. The fascination with long range ballistics has bitten me, and I'll probably go broke searching for that ultimate LR load, and rifle. I must be watching too much TV (Long Range Pursuit), (Extreme Outer Limits), etc. For now its a hobby, but I also do a lot of hunting, and will continue to use the RUM for hunting.
Have you used Barnes, and Bergers on game? I've shot game with my RUM, and was not overly impressed with Swift Scirroco's in factory Rem ammo, although the end result was good. Probably shouldn't complain about that. My loads will be intended for hunting.

 

[cserwin]

Korhil, I appreciate your advice, and willingness to help. I have pretty much made my investment, some of which I'm sure I will be replacing very soon, as with the case trimmer. Apparently you get what you pay for. And I will be looking for precision accuracy. As I get into it I will be picking up more advanced equipment.
I've not actually loaded a round yet, but will soon. Right now waiting on that Wilson micrometer trimmer, with case holders for 300 RUM, and 7mm-08, which I'll also be loading for. Ordered today. I also got a Hornady Lock & Load OAL gauge. Is that worth the cost? Sinclair XL body with bump gauge inserts. I've been doing a lot of reading. Have manuals from Lyman, Speer, Barnes, Nosler, and Hornady. Will continue to read over and over.
I've kept all of my RUM brass from factory ammo purchase. Approximately 700 rounds. I have cleaned all the brass, mostly Remington, and about 100 Barnes. What I am seeing is some case neck splits with the Remington brass. Not a lot, but enough to have me questioning the Rem brass after 1 firing of factory loads. Could this be caused by the factory crimp. The Barnes appears to be in good shape, but has the same type of crimp. Also have purchased some new Nosler brass. I shoot this gun quite a bit, and was seeing a drop in accuracy, and consistency. Anyway the gun is being built by a custom gun builder in North Carolina, and I expect it back within the next few weeks.
Looking forward to it, and as I begin actually loading ammo, I'm sure I'll have more questions. For now I'm waiting on trimmer, and gun back from builder. I could start with that 7mm-08, but still need trimmer, as I have new Rem. brass for it, and will need to do some case trimming. For now I am still in the info gathering, and learning phase.
Stay tuned, more to come.
I appreciate the advice.
Chris

 

[Korhil78]

I have only killed one animal with a berger bullet. It was a javelina at 100 yards with a 25-06. It did the job about like any other bullet would. I have killed a ton of animals (mostly whitetail and mule deer) with the 100 gr barnes TSX out of a 25-06. I have never had anything that I have shot with that 100 gr Barnes bullet run off.

I drew an antelope buck tag in New Mexico this year so I am going to be using the 115 gr berger with my 25-06. I will see how it works out on game.

There are lots of guys on here that use Barnes bullets and lots that use Bergers. They both seem to do the job. Some just prefer one over the other.
I am in the process of getting a custom 338 LM built (just waiting on the action). I will be using the 300 gr Berger OTM so hopefully it will work well.

The OAL gauge is kind of handy to have so that you know how far you can seat your bullets out to. The wilson trimmer will save you a lot of time and will be very consistent on the trim length.

What press do you have?

Since you are starting out, dont just go off on a spending spree and buy anything and everything to try to help you get precision accuracy(unless you are just RICH!). A lot of people go and buy it all at once. They then find out that they spent way too much money and didn't really need all of it. Just buy as you find a need while you are shooting and reloading. If you feel like you need to buy something that will help you but are not sure, just put a post up here and a lot of people are very helpful and will tell you if it is crap or not.

 

[cserwin]

Thats good advice, and I'm guilty of the spending spree. I originally bought a RCBS Rockchucker kit. For now hopefully it will suit my needs. In hindsight I should have done a little more research, and I wish I would have found this site before I got into it.
The good thing about modern technology is availability of information, resources, and forums such as this. A guy should be able to make informed educated decisions on purchase, equipment, techniques, and methods.
Got an elk hunt, and 2 deer hunts coming up, and will be trying 210 gr. Berger, and 180 gr. Barnes TTSX. The TSX comes in 200 gr. weight. May try that. In the end I'll go with what I'm getting the best accuracy from.
Last year was a strike out for me on big game and my freezer is running on empty almost. Hopefully I'll be restocking this year. Did get plenty of birds, and waterfowl though.

 

[cserwin]

Good luck with the antelope, and the 338 build. I'm considering another build, and 25-06 could end up being my choice.