Does 30-30 Ammo Really Need to be Crimped?

[JDinFbg]

The long-standing belief is that 30-30 ammo intended to be shot in a tubular magazine rifle needs to have the bullets crimped to prevent the pressure from the magazine spring and the recoil of the rifle from causing the bullets to be pushed back into the case. I'm wondering if anyone has ever tested this belief? If so, how frequently do bullets, if not crimped, get pushed back into the case? Are we talking every round, 1 in 10, 1 in 100, 1 in 1000? How significant is the problem we're trying to solve by crimping the bullets? Here's why I ask.

I have been testing new loads for my Model 94 Winchester using Hornady's 160 gr. FTX bullet. I mistakenly first bought the 160 gr. bullet designed for the 308 Marlin Express (mfg. #30396). I single-shot loaded these in my rifle when testing group size with different powder loads, and it wasn't until I tried to feed these from the magazine that I realized they were too long to feed. However, they shot wonderfully in my Model 94 when single-shot loaded with the best load giving me a 4-shot group at 100 yds. measuring 0.722". The largest group I got was 2.839". When I obtained and tested the correct Hornady 160 gr. FTX bullet intended for the 30-30 (mfg. #30395), the results were downright dismal. I didn't get any groups smaller than 4.465".

This lead me to put together some dummy rounds using some junk cases and using 4 different bullets. The attached picture shows the 4 dummy rounds I made, all with the bullet seated to where the ogive just contacts the lands in my rifle barrel. The details are as follows:

1 - Hornady 160 gr. FTX 30-30 (mfg. #30395), O.A.L. = 2.602"
2 - Hornady 160 gr. FTX Marlin Express (mfg. #30396), O.A.L. = 2.707"
3 - Unknown brand 150 gr. round point, O.A.L. = 2.632"
4 - Sierra 170 gr. flat point, O.A.L. = 2.533"

SAAMI indicates the maximum cartridge length should be 2.550", but by tests I have found I can feed a cartridge as long as 2.617" in my Model 94 Winchester. The Hornady 30-30 bullet and the Sierra 170 gr. bullet are the only ones that would feed in my rifle loaded out to near where the bullet touches the lands, but the cannelure on the Hornady 30-30 bullet would be nowhere in the proper position for crimping.

Based on seating the bullet to the top of the cannelure, I measured the approximate amount of bullet jump I would get as follows
1 - 0.068" jump
2 - 0.007" jump
3 - 0.075" jump
4 - 0.010" jump

The large bullet jump for the Hornady 160 gr. FTX 30-30 bullet probably explains the dismal results I got with that bullet, and the small jump with the Hornady 160 gr. FTX Marlin Express bullet likely explains why I got some fairly small groups with it. I haven't tested the 150 gr. round nose or the Sierra 170 gr. flat nose, but I would expect that the 170 gr. bullet with its small jump would perform the best.

If I didn't have to seat to the cannelure so I could crimp the bullets for my 30-30, I would have much more flexibility in optimizing the bullet jump and a better chance of producing ammo that shoots well in my rifle. Thus my interest in knowing whether anyone has ever tested un-crimped ammo in
their tubular magazine 30-30 rifles. I'm also wondering if not expanding the case necks before seating the bullet would produce a great enough hold on the bullet to avoid the need for crimping?

 

[243winxb]

Neck tension holds bullets. With the large amount of 30 wcf case neck in contact with the bullet shank, its not going to move easly.

 

[forty_caliber]

The common wisdom here is YES it does need to be crimped. This is to prevent bullet setback from pressure from magazine spring and inertia in the tube when firing.

.40

 

[Charlie98]

NO... if you are shooting a Savage 99...

Yes... and no. As 243 mentions, neck tension holds the bullet, however, if you do not have consistent neck tension you may have bullet setback, or switch to a different lot of brass (thinner brass, for example) with less neck tension. .30-30 brass by it's nature is quite thin at the neck, I would not trust the neck on my brass (very good WW or RP brass, or even Starline...) to hold my bullets in any tube-fed lever-action.

Edit: I mentioned the Savage 99, which has a rotary magazine. I have 2 99's... a .30-30 and a .308; I do not crimp any of those cartridges, although because the 99 is quite picky about OAL, I can't seat them long like I can with my single-shots.

 

[AJC1]

The timing and seating depth is most important. There are normally several seating depth nodes and lever guns are not really known for shooting vld bullets that are very jump Sensitive. Barrel, bullet, powder and seating depth all impact accuracy. I would run a modified seating depth test starting at your maximum functioning oal and work back using the numbers in the Berger seating depth test. If you cannot get inside 2 moa shooting from a bench shift powders or bullet and try again. I'm guessing you have already run an ocw test and were satisfied with those results. It has been discussed ocw vs seating depth first and people argue both ways.

 

[Bfh_auto]

The only way you will get a straight answer is by testing for yourself.
Load one uncrimped round as the first one in the magazine. Fill it with crimped ones. Fire all but the uncrimped one. Refill the mag and repeat. Then remeasure the uncrimped round.

 

[JDinFbg]

The only way you will get a straight answer is by testing for yourself.
Load one uncrimped round as the first one in the magazine. Fill it with crimped ones. Fire all but the uncrimped one. Refill the mag and repeat. Then remeasure the uncrimped round.

Good suggestion. I plan to try that.

 

[edwardware]

Those who test. . . know that neck tension is the story. Crimping is generally not much additional help, and is generally marginal or superfluous in most arms.

One exception is crimping the mouth of the brass deep into a cannelure to resist a tubular magazine. If you get it right, it's sort of a barb that resists inward movement. This requires a lot of crimp, and a tube fed is about the only place I'd bother.

Edit: if you're going to test, don't fire a shot. Measure Base to Ogive (not tip, you're about to mash it), and add it as the last cartridge in a full tube. Feed that cartridge, eject and repeat. The worst moment for set back in a tube mag is when the full stack of cartridges slams the last one into the lifter.

 

[Walkalong]

I crimp for lever guns, which was .30-30 and still is .35 Remington.

 

[JDinFbg]

Neck tension holds bullets. With the large amount of 30 wcf case neck in contact with the bullet shank, its not going to move easly.

243winxb: You make a very good observation that the 30 WCF (a/k/a 30-30) cartridge has a very long neck. It has a proportionately longer neck relative to overall case length compared to many other bottle necked cartridges. Your comment got me to studying the geometry of the case neck relative to the bullets I would consider shooting in this cartridge, and I had an epiphany. I observed that the bearing surface of the Hornady 160 gr. FTX 30-30 boat tail bullet I’m testing would not engage the full length of the case neck if I seat the bullet out to provide minimal jump in my rifle. Photo 1 shows my test round that has the bullet seated out to touch the lands with the same bullet glued to the side of the case at the same elevation. The bottom of the bullet bearing surface is well above the bottom of the case neck. This got me thinking about the methods I could use for expanding the case neck before seating the bullet. Rather than allowing the expander ball on the decapping rod of my RCBS sizing die to expand the full length of the neck, I got to looking at using my dedicated RCBS neck expanding die (which expands by pushing the mandrel into the case neck) to expand only the outer portion of the neck just enough for the bearing surface of the bullet. This will leave a step in the case neck right below the bottom of the bullet bearing surface. Photo 2 shows a sized case along side a case with the outer portion of the neck expanded in this method. I believe this step along with the neck tension will preclude any possibility of the magazine spring and rifle recoil causing bullets to collapse into the case. I think this step will be more effective than any reasonable crimp on the bullet could be. I plan to test this theory.

 

[midland man]

and in singleshot rifles you don't have to crimp them!

 

[JDinFbg]

Based on comments received to my post, I’ve done some more testing and have come up with the following conclusions:

1) For tubular magazine rifles, bullets DO NOT have to be crimped.
2) VLD bullets seem to shoot better with minimal jump

Concerning conclusion #1, Bfh_auto suggested running a test myself. Using the seating method I discussed in post #10 of this thread, I loaded some ammo with none of it being crimped. I measured the length of one round using my Hornady bullet comparator, loaded it first, and then shoved in additional rounds until the magazine tube was full (my Win 94 with 26” barrel holds 8 rounds in the magazine). I fired 7 rounds then ejected and measured the length of the test round. The bullet had not budged. I repeated the process, again firing 7 more rounds with the test bullet at the front of the magazine stack. Measuring again, the bullet had not budged from its original length. Since all of the rounds used in my test were not crimped, I observed each one during the chambering process and could not observe any bullet set-back on any. Thus, using my neck expanding method and a bullet with a bearing surface shorter than the case neck, I conclude that neck tension and the step in the case neck below the bottom of the bullet bearing surface eliminates the need to crimp bullets for shooting in tubular magazine rifles.

Concerning conclusion #2, I followed the suggestion of AJC1 to run the Berger seating depth test:
https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/
I used a modified procedure, shooting two 4-shot groups instead of 3-shot for each bullet jump (I actually shot three 4-shot groups for the zero bullet jump load), and I only tested up to a 0.050” jump. Per previous tests where I had seated the Hornady 160gr. FTX bullet down to the cannelure that resulted in a 0.068” jump, I knew the results were dismal so saw no need to test above a 0.050” jump. I tested jumps of 0.000”, 0.010”, 0.030”, and 0.050”. The results of the test were somewhat inconclusive, but the general indications from the tests were that a smaller bullet jump produces better groups. The curious thing is that the smallest group AND the largest group I got during the tests were both from the rounds that had zero jump. However, not having to crimp the bullets in my loads allows me total freedom to vary the seating depth of my bullets.

 

[GooseGestapo]

Many years ago, .30/30 brass was somewhat thinner than it is today. Back I late 60’s it would have been advisable to crimp. Today, I don’t bother except with cast bullet loads where I’ve used a Lyman M-die to expand a case neck and case mouth for seating a cast bullet. Also, cast bullets Typically have a proper and generous crimp groove that will hold a bullet in place.
Also, it’s often uncanny the accuracy you get with ‘ole cast bullets...

 

[Charlie98]

Based on comments received to my post, I’ve done some more testing and have come up with the following conclusions:

1) For tubular magazine rifles, bullets DO NOT have to be crimped.

Golly... I hate blanket statements like that.

It really depends on your situation... and a whole pile of different things. Neck tension being paramount, but also how much bearing surface the bullet has within the neck, how violent the recoil is, did you flare the case neck to seat the bullet (think cast bullets...) and probably 10 other factors.

It only takes one piece of worn brass with a hairline crack at the neck to allow the bullet to set back enough to spike pressures. You don't necessarily have to crimp the bullet so hard you buckle the shoulder (easy to do with the thin .30-30 brass, ask me, I know...) but a light taper crimp into the cannelure is all it takes (and this is assuming your brass is trimmed to the same length, for a consistent crimp.)

 

[Bfh_auto]

Based on comments received to my post, I’ve done some more testing and have come up with the following conclusions:

1) For tubular magazine rifles, bullets DO NOT have to be crimped.
2) VLD bullets seem to shoot better with minimal jump

Concerning conclusion #1, Bfh_auto suggested running a test myself. Using the seating method I discussed in post #10 of this thread, I loaded some ammo with none of it being crimped. I measured the length of one round using my Hornady bullet comparator, loaded it first, and then shoved in additional rounds until the magazine tube was full (my Win 94 with 26” barrel holds 8 rounds in the magazine). I fired 7 rounds then ejected and measured the length of the test round. The bullet had not budged. I repeated the process, again firing 7 more rounds with the test bullet at the front of the magazine stack. Measuring again, the bullet had not budged from its original length. Since all of the rounds used in my test were not crimped, I observed each one during the chambering process and could not observe any bullet set-back on any. Thus, using my neck expanding method and a bullet with a bearing surface shorter than the case neck, I conclude that neck tension and the step in the case neck below the bottom of the bullet bearing surface eliminates the need to crimp bullets for shooting in tubular magazine rifles.

Concerning conclusion #2, I followed the suggestion of AJC1 to run the Berger seating depth test:
https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/
I used a modified procedure, shooting two 4-shot groups instead of 3-shot for each bullet jump (I actually shot three 4-shot groups for the zero bullet jump load), and I only tested up to a 0.050” jump. Per previous tests where I had seated the Hornady 160gr. FTX bullet down to the cannelure that resulted in a 0.068” jump, I knew the results were dismal so saw no need to test above a 0.050” jump. I tested jumps of 0.000”, 0.010”, 0.030”, and 0.050”. The results of the test were somewhat inconclusive, but the general indications from the tests were that a smaller bullet jump produces better groups. The curious thing is that the smallest group AND the largest group I got during the tests were both from the rounds that had zero jump. However, not having to crimp the bullets in my loads allows me total freedom to vary the seating depth of my bullets.

Something with heavier recoil might still need a crimp.
My experience with 30-30 mirrored yours. But I wanted you to test it for yourself. Different brass, different dies etc can give different results.

 

[AJC1]

Based on comments received to my post, I’ve done some more testing and have come up with the following conclusions:

1) For tubular magazine rifles, bullets DO NOT have to be crimped.
2) VLD bullets seem to shoot better with minimal jump

Concerning conclusion #1, Bfh_auto suggested running a test myself. Using the seating method I discussed in post #10 of this thread, I loaded some ammo with none of it being crimped. I measured the length of one round using my Hornady bullet comparator, loaded it first, and then shoved in additional rounds until the magazine tube was full (my Win 94 with 26” barrel holds 8 rounds in the magazine). I fired 7 rounds then ejected and measured the length of the test round. The bullet had not budged. I repeated the process, again firing 7 more rounds with the test bullet at the front of the magazine stack. Measuring again, the bullet had not budged from its original length. Since all of the rounds used in my test were not crimped, I observed each one during the chambering process and could not observe any bullet set-back on any. Thus, using my neck expanding method and a bullet with a bearing surface shorter than the case neck, I conclude that neck tension and the step in the case neck below the bottom of the bullet bearing surface eliminates the need to crimp bullets for shooting in tubular magazine rifles.

Concerning conclusion #2, I followed the suggestion of AJC1 to run the Berger seating depth test:
https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/
I used a modified procedure, shooting two 4-shot groups instead of 3-shot for each bullet jump (I actually shot three 4-shot groups for the zero bullet jump load), and I only tested up to a 0.050” jump. Per previous tests where I had seated the Hornady 160gr. FTX bullet down to the cannelure that resulted in a 0.068” jump, I knew the results were dismal so saw no need to test above a 0.050” jump. I tested jumps of 0.000”, 0.010”, 0.030”, and 0.050”. The results of the test were somewhat inconclusive, but the general indications from the tests were that a smaller bullet jump produces better groups. The curious thing is that the smallest group AND the largest group I got during the tests were both from the rounds that had zero jump. However, not having to crimp the bullets in my loads allows me total freedom to vary the seating depth of my bullets.

0.000 is touch and is not preferred. Most accuracy gurus go + or - .005 but never touch. It allows for inconsistencies in the entire process and avoids in out touch in the same batch. A lot of people find something around. 020 to be a sweet spot. The Berger test is a rough and a fine with .003 near the best is the fine tuning.